UPR Python tests fail on Linux

When running the pyupr tests on Linux they sometimes hang. It's not the case on OSX.

Aaron confirmed that it's the case on Linux. It looks like the socket connection is not properly closed by ep-engine.

That's the output until the hang:

vmx@cato:~/src/couchbase/pyupr/pyupr:master$ python unit.py
test_add_stream_command (_main_.UprTestCase) ... skipped 'Add stream response is broken in memcached'
test_close_stream_command (_main_.UprTestCase) ... INFO:root:Connecting to 127.0.0.1:12000
INFO:root:Connecting to 127.0.0.1:12000
INFO:root:Closing connection to 127.0.0.1:12000
INFO:root:Closing connection to 127.0.0.1:12000
ok
test_get_failover_log_command (_main_.UprTestCase) ... INFO:root:Connecting to 127.0.0.1:12000
INFO:root:Connecting to 127.0.0.1:12000
INFO:root:Closing connection to 127.0.0.1:12000
INFO:root:Closing connection to 127.0.0.1:12000

And that's the netstat during the hang:

vmx@cato$ netstat|grep 12000 ~/src/couchbase/upr/couchdb:upr15
tcp 0 0 localhost:12000 localhost:55474 ESTABLISHED
tcp 0 0 localhost:55472 localhost:12000 TIME_WAIT
tcp 0 0 localhost:55473 localhost:12000 TIME_WAIT
tcp 0 0 localhost:55474 localhost:12000 ESTABLISHED