Support github enterprise release urls for ISO

[databus23]

This adds support for ISOURL pointing to GitHub Enterprise release API urls.

So this makes the reggae to match

• https://api.github.com/repos/$ORG/$REPO/releases
• https://some.host/api/v3/$ORG/$REPO/releases

Background: We need to maintain a fork of the boot2docker.iso on our internal github applicance to make it work inside our sealed corporate network. Having the boot2docker download and boot2docker upgrade work for us would be a blast.

Cheers

[tianon]

This seems reasonable to me.

@ehazlett @bfirsh probably something that ought to be considered for Machine too?

[tianon]

To make this slightly simpler, couldn't this block of the if just set host = "github.com" and then move the second url = ... outside the else?

[databus23]

You are right. Done

[databus23]

@SvenDowideit Any thoughts on this? Is there a chance for this to be included? Btw the travis build failure seems like an intermittent unrelated one.

[tianon]

The Travis failure will be fixed if you rebase on master. 👍

[ehazlett]

+1 -- we will also add this to machine too.

[tianon]

Thanks @ehazlett ❤️

LGTM

@databus23 if you can rebase on master so we can have this hit Travis for a once-over compile test, I think we're ready to merge 👍

[ehazlett]

yw

[databus23]

Just rebased on master. We have a go from Travis...

[tianon]

Thanks! 👍