After the initial clone of a submodule, no files would be checked out in
the submodule directory if the submodule HEAD was equal to the SHA-1
specified in the index of the containing repository. This fixes the problem
by simply ignoring submodule HEAD for a fresh clone.
Signed-off-by: Lars Hjemli <hjemli@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>