Patch submodules to use read-only URL rather than anonymous

[rizard]

Reviewer: @capveg

[rlane]

You can use SSH even for repositories you can't write to. You do need to have a public key registered with GitHub.

[rizard]

@rlane Someone on the Indigo list was having trouble running the makefile when it tried to clone the submodules. I had trouble myself even though I have my public key registered.

[rlane]

Try "git clone git@github.com:docker/docker". I'm able to clone that without write access.

[rizard]

I can't clone that. Let me make sure I'm using the correct public key. Regardless, should we allow people to clone the submodules without having a public key registered?

[rizard]

@rlane Yep, works now that I'm using the right key pair. But, I'm still wondering if we should require that. The repositories are public.

[capveg]

@rlane agreed that one can still download this without write access (my fault in being imprecise in the description of the problem to Ryan) but IMHO it's just nicer for folks to be able to download the code without a github account. Particularly since they can download the main repo (e.g., indigo) without an account and instead get a weird error about not having permissions when they try to init the submodules.

It's more of a user experience thing -- we've been trying to be vigilant about this on the ONL side for a bit.

Does that change your thinking?