Submodules are supposed to be handled by separate operations, so
we should ignore them on checkout, just like C Git does.
This fix does not add submodule support. We just try harder
to ignore them.
Bug: 343566
Change-Id: I2c5ae1024ea7bb57adf27072da6acc9643018eda
Signed-off-by: Robin Rosenberg <robin.rosenberg@dewire.com>