test suite cannot be run against a server other than localhost

[alsuren]

• There are a bunch of hardcoded "localhost" strings floating about that I had to manually sed out of the way to even get started.
• test/config.hrl.example has SERVERHOST and SERVERNAME.
  • I think SERVERHOST is used as both the domain part of the jid and the dns record to lookup for the purposes of connecting the c2s socket. https://github.com/esl/ejabberd_tests allows you to set these two things separately (which is really useful if your ejabberd cluster has more than one node)
  • SERVERNAME is only used as: test/regression/general.erl: Node = list_to_atom(?SERVERNAME "@" ?SERVERHOST),
  • Probably better to simply set Node as an atom in test/config.hrl ?