Fixes for issues 616 and 617

lib/fog/libvirt/compute.rb

@@ -8,6 +8,7 @@ module Fog
     class Libvirt < Fog::Service
 
       requires :libvirt_uri
+      recognizes :libvirt_username, :libvirt_password
 
       model_path 'fog/libvirt/models/compute'
       model       :server

lib/fog/libvirt/models/compute/nodes.rb

@@ -26,7 +26,7 @@ module Fog
               node_info[param]=nil
             end
           end
-          node_info[:uri]=connection.connection.uri
+          node_info[:uri]=connection.uri
           data << { :raw => node_info }
           require 'pp'
           pp node_info