Add patch from Robert Buchholz:

Add patch from Robert Buchholz:

Backport SLOT support from Portage 2.2 glsa.py

In particular, this is a port of these commits:
commit 856616597ee791efa42dd59760db8e50e72efffd
Author: zmedico <zmedico@ac592a22-f3fe-0310-977e-98394eae9e84>
Date:   Wed Oct 8 22:35:31 2008 +0000

    Fix apparent breakage from r11593 (slot dep support):
    * Handle KeyError from element.getAttribute() in makeAtom() and
    * makeVersion().
    * Avoid 'sre_constants.error: unmatched group' exceptions in
    * revisionMatch()
      when the atom does not have a slot.

svn path=/trunk/gentoolkit/; revision=629