Imrove stability of grok regexes

After the fix, msg rate increased x30
(from 20 to 600+ msg/sec)
Do not use reverse dns resolves for messages!
TODO fix broken multiline for openstack logs

Change-Id: I6729089e6cb007e482e9a8656710a033c199abbd
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>