This actually allows us to check out a supermodule after cloning, although
the submodules themselves will obviously not be checked out, and will just
be empty directories.
Checking out the submodules will be up to higher levels - we may not even
want to!
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <junkio@cox.net>