This is a followup to "Use messaging notifications transport
instead of default" (Ic72fd658fe9b35d39cc3d7da2e4b9fe3454edfba).
The use of NOTIFICATION_TRANSPORT should be global. A unit
test is added; it fails if the variable isn't global.
A typo was addressed in the release notes.
Change-Id: Ie303d79aba893b36a7aecb29c0ff2703f742146e
The usage of oslo_messaging.get_transport is not meant for
notifications; And oslo_messaging.get_notification_transport is
favored for those means. So this change introduces the usage of that
function.
If the settings for the notifications are not set with the
configuration that's under the oslo_messaging_notifications group,
this will fall back to the old settings which are under the DEFAULT
group; just like this used to work.
Change-Id: Ic72fd658fe9b35d39cc3d7da2e4b9fe3454edfba