Fix favorite selection in multiple home views

Use different Gtk.TreeViewColumn for each favorite column,
otherwise only the fist one can be clicked and prevents
populating the other home views.

Slightly cleanup that code.

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>

src/jarabe/desktop/activitieslist.py

@@ -70,17 +70,13 @@ def __init__(self):
         self._model.set_visible_func(self.__model_visible_cb)
         self.set_model(self._model)
 
-        column = Gtk.TreeViewColumn()
-
-        cell_favorites = []
         for i in range(desktop.get_number_of_views()):
-            cell_favorites.append(CellRendererFavorite(i))
-            cell_favorites[i].connect('clicked', self.__favorite_clicked_cb)
-            column.pack_start(cell_favorites[i], True)
-            column.set_cell_data_func(cell_favorites[i],
-                                      self.__favorite_set_data_cb)
-
-        self.append_column(column)
+            column = Gtk.TreeViewColumn()
+            cell = CellRendererFavorite(i)
+            cell.connect('clicked', self.__favorite_clicked_cb)
+            column.pack_start(cell, True)
+            column.set_cell_data_func(cell, self.__favorite_set_data_cb)
+            self.append_column(column)
 
         cell_icon = CellRendererActivityIcon()
         cell_icon.connect('clicked', self.__icon_clicked_cb)