Segfault in test_importworks

* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)    frame #0: 0x00000001097bb9f9 libcouchbase.2.dylib`::lcb_n1ql_cancel(instance=0x00007fcbd75059c0, handle=0x0007fcc074a52890) at n1ql.cc:1110:17   1107     // extra network reads; whereas this function itself is intended as a   1108     // bailout for unexpected destruction.   1109-> 1110     if (handle->prepare_req) {   1111         lcb_n1ql_cancel(instance, handle->prepare_req);   1112         handle->prepare_req = NULL;   1113     }Target 0: (Python) stopped.(lldb) bt* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)  * frame #0: 0x00000001097bb9f9 libcouchbase.2.dylib`::lcb_n1ql_cancel(instance=0x00007fcbd75059c0, handle=0x0007fcc074a52890) at n1ql.cc:1110:17    frame #1: 0x00000001097bba07 libcouchbase.2.dylib`::lcb_n1ql_cancel(instance=<unavailable>, handle=0x00007fcc07496807) at n1ql.cc:1111:9    frame #2: 0x00000001097bba07 libcouchbase.2.dylib`::lcb_n1ql_cancel(instance=<unavailable>, handle=0x00007fcc07496950) at n1ql.cc:1111:9    frame #3: 0x0000000109732abc _libcouchbase.cpython-37m-darwin.so`HttpResult_dealloc(self=0x000000010a1e7530) at htresult.c:66:17 [opt]    frame #4: 0x000000010862ea99 Python`dict_dealloc + 126    frame #5: 0x000000010864598e Python`subtype_dealloc + 1052    frame #6: 0x00000001086a1492 Python`call_function + 950    frame #7: 0x000000010869a312 Python`_PyEval_EvalFrameDefault + 6742    frame #8: 0x000000010860cdec Python`function_code_fastcall + 106    frame #9: 0x00000001086a13bd Python`call_function + 737    frame #10: 0x000000010869a3c6 Python`_PyEval_EvalFrameDefault + 6922    frame #11: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #12: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #13: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #14: 0x000000010860cb25 Python`PyObject_Call + 136    frame #15: 0x000000010869a60f Python`_PyEval_EvalFrameDefault + 7507    frame #16: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #17: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #18: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #19: 0x000000010864a0b6 Python`slot_tp_call + 71    frame #20: 0x000000010860c88e Python`_PyObject_FastCallKeywords + 358    frame #21: 0x00000001086a13b6 Python`call_function + 730    frame #22: 0x000000010869a3c6 Python`_PyEval_EvalFrameDefault + 6922    frame #23: 0x000000010860cdec Python`function_code_fastcall + 106    frame #24: 0x00000001086a13bd Python`call_function + 737    frame #25: 0x000000010869a312 Python`_PyEval_EvalFrameDefault + 6742    frame #26: 0x000000010860cdec Python`function_code_fastcall + 106    frame #27: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #28: 0x000000010860cb25 Python`PyObject_Call + 136    frame #29: 0x000000010869a60f Python`_PyEval_EvalFrameDefault + 7507    frame #30: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #31: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #32: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #33: 0x000000010864a0b6 Python`slot_tp_call + 71    frame #34: 0x000000010860c88e Python`_PyObject_FastCallKeywords + 358    frame #35: 0x00000001086a13b6 Python`call_function + 730    frame #36: 0x000000010869a3c6 Python`_PyEval_EvalFrameDefault + 6922    frame #37: 0x000000010860cdec Python`function_code_fastcall + 106    frame #38: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #39: 0x000000010860cb25 Python`PyObject_Call + 136    frame #40: 0x000000010869a60f Python`_PyEval_EvalFrameDefault + 7507    frame #41: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #42: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #43: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #44: 0x000000010864a0b6 Python`slot_tp_call + 71    frame #45: 0x000000010860c88e Python`_PyObject_FastCallKeywords + 358    frame #46: 0x00000001086a13b6 Python`call_function + 730    frame #47: 0x000000010869a3c6 Python`_PyEval_EvalFrameDefault + 6922    frame #48: 0x000000010860cdec Python`function_code_fastcall + 106    frame #49: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #50: 0x000000010860cb25 Python`PyObject_Call + 136    frame #51: 0x000000010869a60f Python`_PyEval_EvalFrameDefault + 7507    frame #52: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #53: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #54: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #55: 0x000000010864a0b6 Python`slot_tp_call + 71    frame #56: 0x000000010860c88e Python`_PyObject_FastCallKeywords + 358    frame #57: 0x00000001086a13b6 Python`call_function + 730    frame #58: 0x000000010869a3c6 Python`_PyEval_EvalFrameDefault + 6922    frame #59: 0x000000010860cdec Python`function_code_fastcall + 106    frame #60: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #61: 0x000000010860cb25 Python`PyObject_Call + 136    frame #62: 0x000000010869a60f Python`_PyEval_EvalFrameDefault + 7507    frame #63: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #64: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #65: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #66: 0x000000010864a0b6 Python`slot_tp_call + 71    frame #67: 0x000000010860c88e Python`_PyObject_FastCallKeywords + 358    frame #68: 0x00000001086a13b6 Python`call_function + 730    frame #69: 0x000000010869a3c6 Python`_PyEval_EvalFrameDefault + 6922    frame #70: 0x000000010860cdec Python`function_code_fastcall + 106    frame #71: 0x00000001086a13bd Python`call_function + 737    frame #72: 0x000000010869a312 Python`_PyEval_EvalFrameDefault + 6742    frame #73: 0x000000010860cdec Python`function_code_fastcall + 106    frame #74: 0x00000001086a13bd Python`call_function + 737    frame #75: 0x000000010869a312 Python`_PyEval_EvalFrameDefault + 6742    frame #76: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #77: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #78: 0x000000010869a60f Python`_PyEval_EvalFrameDefault + 7507    frame #79: 0x00000001086a1bb1 Python`_PyEval_EvalCodeWithName + 1698    frame #80: 0x000000010860c658 Python`_PyFunction_FastCallDict + 444    frame #81: 0x000000010860d75f Python`_PyObject_Call_Prepend + 131    frame #82: 0x000000010864aaaa Python`slot_tp_init + 80    frame #83: 0x00000001086477d6 Python`type_call + 172    frame #84: 0x000000010860c88e Python`_PyObject_FastCallKeywords + 358