MB-8203: Make sure we can delete a partially initialized bucket

Change-Id: Icab289f08860b1e3e8363be76eaeecc596ff24c8
Reviewed-on: http://review.couchbase.org/26138
Reviewed-by: Michael Wiederhold <mike@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>