MB-23525 [SR]: Clarify EWOULDBLOCK usage for SyncWrites
MB-23525 [SR]: Clarify EWOULDBLOCK usage for SyncWrites

Change-Id: Ie5f938a749b8df1fb7c8433be265010ef2f02e9b
Reviewed-on: http://review.couchbase.org/103486
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Paolo Cocchi <9dd88c9f3e5cbab6e19a6c020f107e0c648ac956@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine