formulary: respect HOMEBREW_BOTTLE_DOMAIN when installing from API

[XuehaiPan]

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Respect HOMEBREW_BOTTLE_DOMAIN when installing from API. This will cause downloading from HOMEBREW_BOTTLE_DOMAIN first when falling back to the default bottle domain if fail.

[Bo98]

This makes sense, thanks!

I wonder though, could it be simplified to:

if bottles_stable["root_url"] != HOMEBREW_BOTTLE_DEFAULT_DOMAIN
  root_url bottles_stable["root_url"]
end

?

[MikeMcQuaid]

Thanks again @XuehaiPan!