ES 2.0 no longer supports valid JSON and disallows dots inside names.
This adds a new "json-elasticsearch" format option which replaces
those dots by the bang ("!") character. So "discarded.full" becomes
"discarded!full".
This is a workaroud. A method that will provide more control over
replacemetns will be implemented some time in the future. For
details, see below-quoted issue tracker.
closes https://github.com/rsyslog/rsyslog/issues/713
0f5595c074