Making models compatible with SQLAlchemy > 0.8.1

Change-Id: I245e40138fd76754d928fa67cfd7647342d8743f
Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/analytics/wikimetrics
Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/analytics/wikimetrics
Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/analytics/wikimetrics
Making faulty test not run (code to implement revert logic is not there)

Change-Id: I48021c9603664e05417a58eb6b3b4d05caa5a404