Some tests were using domain names that were intended to be "fake", but are
actually registered domain names (such as domain.com, registry.com, mytest.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>