fix inheritance problem with mixin

- a mixin should not inherit from module then it has Parameters
- Parameters in mixins must be complete, not just overrides
- check precedence of read_<param> or handler

Change-Id: I72d9355a1982770d1a99d9552a20330103c97edb

secop/client/__init__.py

@@ -495,9 +495,12 @@ class SecopClient(ProxyClient):
     def _set_state(self, online, state=None):
         # treat reconnecting as online!
         state = state or self.state
-        self.callback(None, 'nodeStateChange', online, state)
-        for mname in self.modules:
-            self.callback(mname, 'nodeStateChange', online, state)
+        try:
+            self.callback(None, 'nodeStateChange', online, state)
+            for mname in self.modules:
+                self.callback(mname, 'nodeStateChange', online, state)
+        except Exception as e:
+            self.log.error('ERROR in nodeStateCallback %s', e)
         # set online attribute after callbacks -> callback may check for old state
         self.online = online
         self.state = state