=pro all non-words must be replaced with _, for statsd keys
Merge pull request #15069 from ktoso/wip-better-stats-keys

=pro all non-words must be replaced with _ for statsd keys
=act #13966 Change wrong default discardOld in UntypedActor become

(cherry picked from commit 2aada3b5a857552f9d7854a19cd72d77e6a52b9b)
Merge pull request #15096 from akka/wip-13966-become-discardOld-master-patriknw

=act #13966 Change wrong default discardOld in UntypedActor become (for validation)
Merge remote-tracking branch: upstream/master