When resetting the working tree files recursively, the working tree
of submodules are now also reset to match.
* sb/submodule-update-reset-fix:
submodule: submodule_move_head omits old argument in forced case
unpack-trees: oneway_merge to update submodules
t/lib-submodule-update.sh: fix test ignoring ignored files in submodules
t/lib-submodule-update.sh: clarify test