[Merge] ~cjwatson/software-properties:new-ppa-domains into software-properties:ubuntu/master

[Brian Murray]

When I run the autopkgtests for this package with squid.internal as the proxy server some of them end up failing, despite my having added launchpadcontent.net to the no_proxy environment variable. So there might be something else going, but I haven't investigated it thoroughly.
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https://code.launchpad.net/~cjwatson/software-properties/+git/software-properties/+merge/414567
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~cjwatson/software-properties:new-ppa-domains into software-properties:ubuntu/master.