Imrove stability of grok regexes

After the fix, msg rate increased x40
(from 20 to 800+ msg/sec)
Note:don't use reverse dns resolves or GREEDYDATA
TODO fix broken multiline for openstack logs

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