submodule: fix confusing variable name

cmd_summary reads the output of git diff, but reads in the submodule path into a
variable called name.  Since this variable does not contain the name of the
submodule, but the path, rename it to be clearer what data it actually holds.

Signed-off-by: Brian M. Carlson <sandals@crustytoothpaste.net>
Acked-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule: don't print status output with ignore=all

git status prints information for submodules, but it should ignore the status of
those which have submodule.<name>.ignore set to all.  Fix it so that it does
properly ignore those which have that setting either in .git/config or in
.gitmodules.

Not ignored are submodules that are added, deleted, or moved (which is
essentially a combination of the first two) because it is not easily possible to
determine the old path once a move has occurred, nor is it easily possible to
detect which adds and deletions are moves and which are not.  This also
preserves the previous behavior of always listing modules which are to be
deleted.

Tests are included which verify that this change has no effect on git submodule
summary without the --for-status option.

Signed-off-by: Brian M. Carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>