Fix an crash in conflict detection when no movie is selected

FreeboxMoviePlanner.py

@@ -305,6 +305,7 @@ class FreeboxMoviePlanner:
 
     def checkForConflicts(self):
         programmed_movies = self.freebox.Pvr.Getting_the_list_of_precords()
+        if programmed_movies:
             conflicting_movies = [m for m in programmed_movies if m['conflict']]
             if conflicting_movies:
                 print(