It's been re-cloned and is being updated every 10 minutes.
Note that this was a non-fast-forward updates, so "git pull" on existing checkouts won't work, you'll have to re-clone.
On the plus side this is now being cloned directly from svn, e.g. this is the latest commit:
git-svn-id: svn+ssh://svn.wikimedia.org/svnroot/mediawiki/trunk@86256 dd0e9695-b195-4be7-bd10-2dea1a65a6b6
This means that using this to bootstap your own git-svn checkout (to use for further development) should be possible now, but I don't have instructions for how to do that, patches to http://www.mediawiki.org/wiki/Git#Rebuilding_SVN_metadata welcome.
Note that this is still out of date:
http://gitorious.org/mediawiki
I don't know who maintains it, but if there's demand for having one on gitorious I'd be happy to update that one too. It's just a matter of adding a couple of extra pushes here:
https://github.com/avar/mediawiki-mirror/blob/master/mediawiki-mirror.sh#L22