tests: kill all started processes on exit

Just killing MongoDB is not enough, we also need to kill processes such
as the cat ones used to read the fifo.

Change-Id: I3fd99e333e69625e3872e24b9337cad17d46d737
Removes use of timeutils.set_time_override

The set_time_override function in timeutils was written as a
helper function to mock utcnow for unittests before 'mock' was
generally used. Now that we have mock and fixture, we no longer
need to use it.

Change-Id: I7c3793d7a442dc85aec405041c3c9ce6f7503bd8
Closes-Bug: #1266962
Sync gettextutils from Oslo

Latest oslo-incubator gettextutils commit:
9d529dd Make Message keep string interpolation args

Bring in latest fixes to the new Message class.

bp i18n-messages

Change-Id: I9ac8a0da9ea3b7b393f81c255332d83bbcab1da9
Change meter_id to meter_name in generated docs

All operations on API level use meter name.
GET or POST /v2/meters/name_of_meter.
In docs we have meter_id, it is confusing, because meter_id is
syntetic UUID that is not used in DB ops.

The change should be done in v2.py because docs are generated
automatically and it's content is based on variables names from
the code.

Change-Id: I29abbefdaaa039f790f78fac102ede933d61d911
Merge "Removes use of timeutils.set_time_override"
Merge "Change meter_id to meter_name in generated docs"
Merge "tests: kill all started processes on exit"
Merge "Sync gettextutils from Oslo"