[icon view] Handle an empty model gracefully
[icon view] Handle an empty model gracefully

When encountering an empty model clutter_model_get_first_iter () returns NULL.
Avoid dereferencing this when rotating around the while loop. But do continue
to test if the number of rows in the model (zero) is less than the number of
children in container and remove those excess children.

jonnylamb/mx,jonnylamb/mx,pwithnall/mx,jonnylamb/mx,jonnylamb/mx,clutter-project/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,clutter-project/mx,pwithnall/mx,clutter-project/mx