MB-10839 Fixing the string length in unicode comparision

Change-Id: I557651e59e3807e143d680dcbabdb0e8acbdccc5
Reviewed-on: http://review.couchbase.org/36133
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>