CBQE-1284: infinite loop in BucketCreateTask.check

Change-Id: Ic166dce094b1350ea5387809863f5ae496a27f56
Reviewed-on: http://review.couchbase.org/26245
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>