xcollazo, otto: Backport for [[gerrit:1276699|Remove stream 'mediawiki.dump.revision_content_history.reconcile.rc0' (T417694)]], [[gerrit:1276397|EventStreamConfig - add rc0 streams for html and feature count change (T423920)]] synced to the testservers (see https://wikitech.wikimedia.org/wiki/Mwdebug). Changes can now be verified there.