bugfix: duplicate rows in TagStorage for racks

When a rack is created with taglist specified, the
produceTagsForNewRecord() call took place 2 times: first from
commitAddObject with the 'object' realm, and then again from an
ophandler with the 'rack' realm.

Removed the ophandler calls to produceTagsForNewRecord() and fixed the
commitAddObject to respect pseudo-realms (racks, locations, rows)