CBQE-1284: infinite loop in BucketCreateTask.check

Change-Id: I9d0c700040889bd70f24a5f3887817831aaac1c6
Reviewed-on: http://review.couchbase.org/27045
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>