parameters with a handler are polled by default

parameters with a common commandhandler need only one poller item

Change-Id: Ie2e20cf7bcebc67ca96d58455323f01f528b25ab
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21951
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

secop/params.py

@@ -139,9 +139,8 @@ class Parameter(Accessible):
             datatype.setProperty('unit', unit)
         super(Parameter, self).__init__(**kwds)
 
-        # note: auto-converts True/False to 1/0 which yield the expected
-        # behaviour...
-        self.properties['poll'] = int(self.poll)
+        if self.handler and not self.poll:
+            self.properties['poll'] = True
 
         if self.constant is not None:
             self.properties['readonly'] = True