GUI-129: support ssl cert verification for eucalyptus connections

converted EucaAuthenticator to use httplib (like boto) so that we could re-use the CertValidatingHTTPSConnection boto uses for cert validation.
Use EucaAuthenticator directly instead of going through views/__init__.py:get_connection()
when AWSQueryConnection calls AWSAuthConnection, it passes "None" as the default for host, so that's why I did that. Both of those are part of boto.