submodule add: fix handling of --reference=<repo> option
submodule add: fix handling of --reference=<repo> option

Doing a shift here is wrong because there is no extra
argument to consume when "--reference=<repo>" is used (note
the '=' instead of a space).

Signed-off-by: Stefan Zager <542cb5b73770f9741bae40d34cf7a192bc7ad2cc@google.com>
Signed-off-by: Jeff King <696e3fbcf235d40b6ea1ebd61c87cbea79d444e7@peff.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git