quick frontend (widgets): fixed widget creation in getOrCreateWidget:

when a new widget was created, it was overwritting the exiting instances list. This patch
fixes it.

sat_frontends/quick_frontend/quick_widgets.py

@@ -225,7 +225,7 @@ class QuickWidgetsManager(object):
             # we need to create a new widget
             log.debug("Creating new widget for target {} {}".format(target, cls))
             widget = cls(*_args, **_kwargs)
-            widgets_map[hash_] = [widget]
+            widgets_map.setdefault(hash_, []).append(widget)
 
             if on_new_widget == C.WIDGET_NEW:
                 self.host.newWidget(widget)