curds: Set collection random value through the Playlist class

We still fix the value, but if we ever add extra handling in the base
class then we'll be able to catch it.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

curds/playlist/collection.py

@@ -9,5 +9,4 @@ class CollectionPlaylist(playlist.Playlist):
         self.loop = True
 
     def set_loop(self, loop):
-        self.loop = True
-        return self.loop
+        return playlist.Playlist.set_loop(self, True)