LOG.warn etc. should be translated separately and thus messages need to
be marked with _LW for LOG.warn, _LI for LOG.info and _LE for LOG.errors
and LOG.exception.
Mark all LOG invocations with proper translation marker.
Use ',' instead of '%' when adding variables to log messages to allow
lazy evaluation.
Add new hacking checks for these.
Change-Id: I31d3ee50f30c63d7d647b1c2b1eae50bf96f0c74