Adds regions_list

Adds a regions_list attribute to the connection object - this is populated during authentication. This comes from a [JIRA request]( https://issues.apache.org/jira/browse/DTACLOUD-443) against the [Apache Deltacloud](http://deltacloud.apache.org) project.  Looks like:

    => {  "region-a.geo-1" => [{:service=>"object-store", :versionId=>"1.0"},
                                           {:service=>"identity", :versionId=>"2.0"}],
             "region-b.geo-1"=> [{:service=>"identity", :versionId=>"2.0"}],
             "az-2.region-a.geo-1"=>[{:service=>"image", :versionId=>"1.0"},
                                            {:service=>"volume", :versionId=>"1.1"},
                                            {:service=>"compute", :versionId=>"1.1"}],
            "az-1.region-a.geo-1"=>[{:service=>"image", :versionId=>"1.0"}, 
                                             {:service=>"volume", :versionId=>"1.1"}, 
                                             {:service=>"compute", :versionId=>"1.1"}]}
i.e.

        {:region_id => [ {:service=>"service_type", :versionId=>"version_string"}, ... {}   ], ...      }

marios