Make Slack notifications work again
Make Slack notifications work again

Slack notifications work by tapping in to the history for a given
service, and use a set of regexps to determine which history entries to
forward to the Slack channel. In a recent change, we changed "Release"
to "Regrade", but did not update the regexp to catch it.

squaremo/flux,squaremo/flux,weaveworks/flux,weaveworks/flux