The old 'watcher_messaging' section of the Watcher configuration file
has now been replaced by the more standard oslo.configuration one.
DocImpact
Change-Id: Ie027df023e6133f3188e57b42846083f28c282bd
Following the update of the project requirements, we should now
use the oslo.config namespace of oslo.log when generating ou
Watcher config sample file.
Change-Id: I7a1f3d555534b40c041b7f042f19fae231b7e80c
Closes-Bug: #1518297