Updated openstack/openstack
Project: openstack/oslo-incubator  df774ff43fb750c5f2b3a97355a437744c5d3873

Import PublishErrorsHandler from oslo.messaging

log_handler graduated and it's in oslo.messaging now.
Remove unnecessary try/import.

Change-Id: I78cdeba0cb90148b6ebd2f23f1aecb5d1f7ceef8