combobox.py should catch exception when icon fails to load

[walter]

I thought I had reported this before and I had fixed it in my local copy, but I cannot find the ticket.

The Balloon activity has a broken icon svg file which is causing the append_item method in combobox.py to throw an exception and prevent Sugar from launching properly.

pseudo patch:
lines 116-117

- pixbuf = gtk.gdk.pixbuf_new_from_file_at_size(
- file_name, width, height)

+ try:
+ pixbuf = gtk.gdk.pixbuf_new_from_file_at_size(
+ file_name, width, height)
+ except:
+ pixbuf = None

This happened when I installed the latest update to Sugar which apparently overwrote the patch I had applied earlier.