hang in dataport.(*Server).Close

Observed this while running some random tests. One of the drop index gets stuck due to this. The Close call to dataport never returns.

1 @ 0x4031ba3 0x4040887 0x403fde2 0x4093b7b 0x4659288 0x417d1d0 0x417d720 0x4061b91

1. 0x4093b7b github.com/couchbase/indexing/secondary/common.FailsafeOp+0x22b /Users/deepkaran/workspace/cb_watson_r/goproj/src/github.com/couchbase/indexing/secondary/common/util.go:156
2. 0x4659288 github.com/couchbase/indexing/secondary/dataport.(*Server).Close+0x1d8 /Users/deepkaran/workspace/cb_watson_r/goproj/src/github.com/couchbase/indexing/secondary/dataport/server.go:207
3. 0x417d1d0 github.com/couchbase/indexing/secondary/indexer.(*mutationStreamReader).Shutdown+0x130 /Users/deepkaran/workspace/cb_watson_r/goproj/src/github.com/couchbase/indexing/secondary/indexer/stream_reader.go:141
4. 0x417d720 github.com/couchbase/indexing/secondary/indexer.(*mutationStreamReader).listenSupvCmd+0xc0 /Users/deepkaran/workspace/cb_watson_r/goproj/src/github.com/couchbase/indexing/secondary/indexer/stream_reader.go:199

Full goroutine and logs attached.