This changes the way git-submodule uses .gitmodules: Subsections no longer
specify the submodule path, they now specify the submodule name. The
submodule path is found under the new key "submodule.<name>.path", which is
a required key.
With this change a submodule can be moved between different 'checkout paths'
without upsetting git-submodule.
Signed-off-by: Lars Hjemli <hjemli@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>