Do not close listening connection on secondary masters.

neo/master/app.py

@@ -362,6 +362,7 @@ class Application(object):
         # Restart completely. Non-optimized
         # but lower level code needs to be stabilized first.
         for conn in self.em.getConnectionList():
+            if not conn.isListening():
                 conn.close()
 
         # Reconnect to primary master node.