Crashes when writing icons

[ximion]

When writing the icons, this issue happens:

Saved icon pushpin.svg.
Saved icon menu.png.
Traceback (most recent call last):
  File "/usr/local/bin/dak", line 241, in <module>
    main()
  File "/usr/local/bin/dak", line 221, in main
    module.main()
  File "/srv/dak/dak/dak/generate_metadata.py", line 1036, in main
    process_suite(suite)
  File "/srv/dak/dak/dak/generate_metadata.py", line 1000, in process_suite
    pool.saver()
  File "/srv/dak/dak/dak/generate_metadata.py", line 910, in saver
    icon_bool = cg.fetch_icon(self._values)
  File "/srv/dak/dak/dak/generate_metadata.py", line 862, in fetch_icon
    path, self._cdata._file, values)
  File "/srv/dak/dak/dak/generate_metadata.py", line 830, in save_icon
    icon_data = DebFile(filepath).data.extractdata(icon)
SystemError: E:read, still have 16855 to read but none left

Wrapping it in a try..except block is probably safe for now.