Adapt to changes in the icon API.

shell/model/homeactivity.py

@@ -103,7 +103,7 @@ class HomeActivity(gobject.GObject):
         if self._activity_info:
             return self._activity_info.icon
         else:
-            return 'theme:image-missing'
+            return 'image-missing'
     
     def get_icon_color(self):
         """Retrieve the appropriate icon colour for this activity

shell/view/frame/overlaybox.py

@@ -24,7 +24,7 @@ class OverlayBox(hippo.CanvasBox):
 
         self._shell = shell
 
-        icon = IconButton(icon_name='theme:stock-chat')
+        icon = IconButton(icon_name='stock-chat')
         icon.connect('activated', self._overlay_clicked_cb)
         self.append(icon)