Pullquote saves now allow post saves

See: https://github.com/GigaOM/gigaom/issues/6268

Tested:
* 2 new pullquotes - __result:__ both pullquote posts created, ids added in contents of post
* 2 old pullquotes with no changes - __result:__ pullquotes retain ids, pullquote posts remain
* 2 old pullquotes with different pullquote contents - __result:__ pullquotes retain ids, pullquote post excerpts were updated as expected
* 1 new pullquote, 1 old - __result:__ new pullquote added and id added to contents, old pullquote retains id

In all cases, the contents of the post was updatable.