Feature #2887: Support a proxy configuration option for the AWS hybrid

cloud

src/vmm_mad/remotes/ec2/ec2_driver.conf

@@ -1,3 +1,4 @@
+proxy_uri:
 regions:
     default:
         region_name: us-east-1

src/vmm_mad/remotes/ec2/ec2_driver.rb

@@ -222,6 +222,10 @@ class EC2Driver
             'secret_access_key' => @region['secret_access_key'],
             'region'            => @region['region_name'])
 
+        if (proxy_uri = public_cloud_ec2_conf['proxy_uri'])
+            AWS.config(:proxy_uri => proxy_uri)
+        end
+
         @ec2 = AWS.ec2
     end