bug in Attached (fix after change 31470)

An attached property may be defined with mandatory=False.
In this case, when no value or an empty string is given,
<modobj>.<attached_mod> must return None after initialisation.

+ remove 'dispatcher' level from the logger hierarchy on modules

Change-Id: Icee3ae3f9142cd7a910c579ae1ffaa35f93cee03
Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/32187
Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

frappy/protocol/dispatcher.py

@@ -227,7 +227,7 @@ class Dispatcher:
             return None
         else:
             try:
-                modobj = cls(modulename, self.log.getChild(modulename), opts, self.srv)
+                modobj = cls(modulename, self.log.parent.getChild(modulename), opts, self.srv)
             except ConfigError as e:
                 self.errors.append(f'error creating module {modulename}:')
                 for errtxt in e.args[0] if isinstance(e.args[0], list) else [e.args[0]]: