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()
no. I wasn't to be clear (in the code) that the conn object wasn't needed anymore, so I set it to None so that it cannot be used.