Use RFC 2606 reserved invalid DNS name in tests.

This test used a DNS name which, while currently not existing, is not
actually reserved. This can manifest as a test failure on poorly
configured (like Time Warner Cable) networks. This changes said DNS
name to one using a reserved invalid top level name as specified in
RFC 2606.
Merge pull request #176 from gabrielg/master

Use RFC 2606 reserved invalid DNS name in tests.