[RFE] git submodule foreach where initialized

Hi All,

I have hit an edge condition that I think may need a command option. When
cloning, we sometimes ignore a specific submodule (because we don't need it
on the platform we are building in this case).

The git submodule foreach command reports an error: fatal: No url found for
submodule path 'sub1' in .gitmodules

In our situation, this can be bypassed because we don't care about sub1. My
thought is that some option like --init-only or --ignore-uninit might be
useful to bypass this condition and allow the foreach to run on all valid
submodules. Does that make sense?

Regards,
Randall