Well, yes, that looks pretty much like the same problem. When I talked to Yocto folks on the IRC they mentioned that they saw sporadical git clone problems on their repo, but that self-resolved around the time i talked to them (and I confirmed that by runnign the build, some other folks did as well). Maybe the problem has returned?
Anyways, try applying the workaround with MIRROR list I've posted there, should be good enough.
And one more thing - just copying the bbclass file from one Yocto version to another is prone to errors, because they may change stuff in between the versions. I hope you rather reviewed both old and new files and merged the changes?