'make prep' breaks on private branches.

[Roland McGrath]

> Here is what I'm doing:
> 
> fedpkg clone kernel
> fedpkg switch-branch f14
> git checkout -b pnfs-all-2.6.35-2010-08-05

Make that 'git checkout --track -b pnfs-blah-blah origin/f14/master'.
Or, equivalently, after the fact, do:
	git config branch.pnfs-blah-blah.remote origin
	git config branch.pnfs-blah-blah.merge refs/heads/f14/master

> git.errors.GitCommandError: 'git config --get branch.pnfs-all-2.6.35-2010-08-05.merge' returned exit status 1: 

fedpkg is using this to figure out which dist to build for.
Having it set up also means that 'git pull' et al will automagically
know to merge the f14/master branch into your branch.


Thanks,
Roland