Fix Data race in TestStoreCrashRecovery
Fix Data race in TestStoreCrashRecovery

Write at 0x00c4200b05a8 by goroutine 24:
github.com/couchbase/moss.(*Store).persist()
/home/couchbase/jenkins/workspace/moss-master/gopath/src/github.com/couchbase/moss/store.go:162

Previous read at 0x00c4200b05a8 by goroutine 52:
github.com/couchbase/moss.TestStoreCrashRecovery()
/home/couchbase/jenkins/workspace/moss-master/gopath/src/github.com/couchbase/moss/store_test.go:2110

Change-Id: I3c3790b697bcbe8793a20ba6bf10110ac84a467e
Reviewed-on: http://review.couchbase.org/90241
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>
Tested-by: Sundar Sridharan <333a3f71d3ad6e01fc953c4fa06bc1f3cd014910@couchbase.com>

couchbaselabs/moss