Remove RPC notification from transaction in create/update port

Removing notifications to the L3 agent from within the transaction in
create_port and update_port eliminates many lock wait timeouts in the
dvr check queue job and in scale testing locally.

Since this patch leaves context unused in _process_port_binding, the
argument is removed from the method.

Closes-Bug: #1371732

Change-Id: Ibd86611ad3e7eff085d769bdff777a5870f30c58
Merge "Remove RPC notification from transaction in create/update port"