The release process seems a bit backward IMHO. Why did 7.9 become 8.0 in the first place if it wasn't meant to be feature frozen?
Also, shouldn't there be a "master" git branch where development takes place? When it's time for feature freeze in preparation for a release, a release branch (say 8.2) would be forked and reserved for bugfixes. New features would be pushed/merged to "master". Adopting this workflow would at this point be as easy as renaming the branch "8.1" to "master". :-)