Fix std variable name.

cloudcontrol/node/node.py

@@ -331,8 +331,8 @@ class MainLoop(object):
 
     def start(self):
         logger.info('Starting node')
-        for signal in self.signals.itervalues():
-            signal.start()
+        for signal_ in self.signals.itervalues():
+            signal_.start()
         logger.debug('About to connect')
         self.connect.start()
         logger.debug('About to start ev_loop')