Commit 27b2797f7d added a local implementation
of this function, so let's use the local variant to (slightly) reduce the
dependency on moby's registry package.
Also made some minor cleanups.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Some tests were using domain names that were intended to be "fake", but are
actually registered domain names (such as mycorp.com).
Even though we were not actually making connections to these domains, it's
better to use domains that are designated for testing/examples in RFC2606:
https://tools.ietf.org/html/rfc2606
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>