ceilometer tests need to be enabled/cleaned

- re-enable a bunch of tests that currently aren't being discovered
and thus never run.
- delete notificationclient and its tests since no one uses it.

Change-Id: I50ad04bc22b06c718ce47052c64c95165e54efe8
Fixes: Bug#1197545
Merge "ceilometer tests need to be enabled/cleaned"