Corrects typo "a other" -> "another"
Corrects typo "a other" -> "another"

Fixes typo ceiometer/publisher/messaging.py.

Change-Id: I3bf07102f8a57567b2b67856c413da58e440c474

openstack/ceilometer,idegtiarov/ceilometer,ityaptin/ceilometer,openstack/ceilometer,idegtiarov/ceilometer,ityaptin/ceilometer