Fixed issue in local changes forwarder, where a
PostOnlyTransactionHandler was used inconsistently during change
forwarding. This was incorrect because this would provoke origin posting
of change which local changes upwarders would catch and start duplicate
forwarding. Now, NullTransactionHandler is used, such that changes are
not posted.

Signed-off-by: Jakob Brandsborg Ehmsen <jakobehmsen.github@gmail.com>