add more debugging so we know successful update

utils/he_ipv6.py

@@ -231,6 +231,8 @@ class TunnelBroker(object):
         if status.lower() not in ('good', 'nochg'):
             logger.error('Returned following failure message: {0}'.format(req.content.decode('utf-8')))
             raise RuntimeError('Client IP update returned failure')
+        else:
+            logger.debug('Returned success message: {0}'.format(req.content.decode('utf-8')))
         if self.ipr and oneshot:
             self.ipr.close()
             self.ipr = None