Fixes https://taskotron.fedoraproject.org/taskmaster/builders/x86_64/builds/63826 that was caused by http://koji.fedoraproject.org/koji/buildinfo?buildID=632072 ('el7' not in release).
Also it removes blacklisted_releases, as @kparal suggested, we don't have to add a new tag everytime there's new epel release (although it's not often).
Since you removed the blacklist feature, this message might be slightly confusing. What about
?