Runaway "git remote" if group definition contains a remote by the same name

Hi,

it is also a way to create a fork bomb out of the innocent tool on platforms where pressing Ctrl-C does not terminate subprocesses of the foreground process (like, of course, Windows).

To reproduce, run

   git -c remotes.origin='origin other' remote update origin

I just cannot look at it right now, and have to resolve to only reporting the problem to warn people. Something seems to resolve the remotes group definition over and over again.