Repo functionality should still work even when installed pigments are corrupted

[David D Lowe]

Steps to recreate the bug:
1) Install Epidermis and a few skins.
2) Open a file manager with root privileges and go to /boot/grub.
3) Rename the 'splashimages' folder to whatever you want.
4) Open Epidermis.
5) As expected, error messages appear.
6) However, you cannot click "Find more" and install or uninstall pigments. Epidermis just freezes, it displays an empty message dialog and prints an error similar to this one in the terminal:
Traceback (most recent call last):
  File "/usr/share/pyshared/epidermis/loadrepo.py", line 239, in run
    self.run2()
  File "/usr/share/pyshared/epidermis/loadrepo.py", line 249, in run2
    self.check_online()
  File "/usr/share/pyshared/epidermis/loadrepo.py", line 341, in check_online
    load_cached_repo()
  File "/usr/share/pyshared/epidermis/loadrepo.py", line 135, in load_cached_repo
    % {'newPigmentCodename':newPigmentCodename, 'type':pt}))
Exception: Cannot find installed pigment: linux-mint type grub
Cannot find installed pigment: linux-mint type grub

What should happen: "Find more" should be usable even when pigments are badly installed. Furthermore, they should be an easy way to remove corrupted pigments.

I'm using Epidermis 0.5 on Ubuntu Karmic with Python 2.6.4.