Description of problem:

Upstream stabe/liberty has already identified and fixed a considerable
amount of bugs which are of interest:

82b76dc re-implement thread safe fnmatch
fc00820 Updated from global requirements
1fae4dd Add WebTest to test-requirements.txt
415ee34 Imported Translations from Zanata
20f88cc add reno for release notes management
949c343 add first reno-based release note
81dded7 avoid unnecessary inner join in get_resources() for SQL backend
5e33801 Update .gitreview for stable/liberty
6aae92f Add Liberty release note link
ca45db1 avoid using isolation level
c91852d Updated from global requirements
16af61a avoid generate temporary table when query samples
2a43a81 Ensure the test data sample has correct signature
2dd9b77 Remove dependency on sphinxcontrib-docbookrestapi
05416c2 Updated from global requirements
46d2ede Switch to post-versioning
be0f965 support mysql+pymysql in functional test
d91e191 If mongodb_replica_set is empty do not pass it to client
e051e22 Add missing ceilometerclient repo location
5cdeeac Skip bad meter definitions instead of erroring out

We should rebase onto 5.0.1 in advance of OSP8 in order to leverage the upstream stable-maint efforts.

The published upstream tarball is here: http://tarballs.openstack.org/ceilometer/ceilometer-5.0.1.tar.gz