misc: replaced all "dummy" by the more conventional and readable "__" ("_" being used for gettext)

sat_frontends/quick_frontend/quick_app.py

@@ -123,7 +123,7 @@ class ProfileManager(object):
         autoconnect = C.bool(value_str)
         if autoconnect and not self.connected:
             self.host.connect(
-                self.profile, callback=lambda dummy: self._plug_profile_afterconnect()
+                self.profile, callback=lambda __: self._plug_profile_afterconnect()
             )
         else:
             self._plug_profile_afterconnect()
@@ -557,7 +557,7 @@ class QuickApp(object):
 
     def connect(self, profile, callback=None, errback=None):
         if not callback:
-            callback = lambda dummy: None
+            callback = lambda __: None
         if not errback:
 
             def errback(failure):
@@ -727,7 +727,7 @@ class QuickApp(object):
             extra = {}
         if callback is None:
             callback = (
-                lambda dummy=None: None
+                lambda __=None: None
             )  # FIXME: optional argument is here because pyjamas doesn't support callback
                #        without arg with json proxy
         if errback is None: