Send IRC line only after transaction commit

RecentChanges IRC lines were being sent out before commiting
the transaction.  In the rare case of a transaction failing and
being rolled back that IRC line is already sent and is now invalid.

Patch moves all recent changes handling behind deferred updates that
only run on successfull commit.

Change-Id: I960effe8c728b7948fa6639d114397b3f587ccb4