Python3.5 tests were not running because Python3 has not
Queue module (instead have queue module). Commit
does not fix failing tests but gives an insight in what
exactly is failing and allows to fix them in future.
Also applied sixer utility to fix common Py2-Py3 compatybility
issues.
Additionally:
* removed unconstrained mysql and psycopg drivers from tox.ini.
Instead added them to test-requirements to be picked up
by requirements bot. That also allowed to remove 3 tox
environments.
* added removing .testrepository/times.dbm (may cause py3 environment
to fail if present)
Change-Id: I9bcc33dad80fdfbf60d95c4bb0ce7f79f642a414
c9f0a8e63c