bug 822759 - more debugging patches to diagnose problem in -dev

* re-enabled the tests for test_metlog_*
* added double logging for each of the generate_error events that
  route through metlog. one through the default metlog instance,
  another through the local metlog client instance
* bumped to metlog-py 0.9.10 to see the full client configuration as a
  JSON blob
* pulled out all METLOG_CONF configuration from settings_base and just
  set it at once.  This has to be done in settings_mkt.py and
  settings_addons.py
write review modal WIP