We should use the fully qualified domain name to prevent CDN/dns issues.. people have reported that http://thetvdb.com doesn't work for them while http://www.thetvdb.com does. Plus we already use www for other calls and as the 'base'. So these were just two oddball entries that weren't.
Merge pull request #560 from thezoggy/dev--tvdb-FQDN

Use FQDN for thetvdb url