Fix Mutation Queue Test Case

Change-Id: Ie01d08df5f64b6ba14e7a274d1aced79b1e8ade7
Reviewed-on: http://review.couchbase.org/39261
Reviewed-by: John Liang <johliang00@gmail.com>
Reviewed-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>
Tested-by: Deepkaran Salooja <deepkaran.couchbase@gmail.com>