Adding delete agent token coverage of api

lib/fog/rackspace/monitoring.rb

@@ -63,6 +63,7 @@ module Fog
       request      :update_entity
       request      :update_alarm
 
+      request      :delete_agent_token
       request      :delete_check
       request      :delete_entity
 

lib/fog/rackspace/requests/monitoring/delete_agent_token.rb

@@ -0,0 +1,17 @@
+module Fog
+  module Rackspace
+    class Monitoring
+      class Real
+
+        def delete_agent_token(token_id)
+          request(
+            :expects  => [204],
+            :method   => 'DELETE',
+            :path     => "agent_tokens/#{token_id}"
+          )
+        end
+      end
+    end
+  end
+end
+