Do not inject GLSAs into the checkfile when fixing them

Do not inject GLSAs into the checkfile when fixing them

There is no reason applied GLSAs must be stored in a checkfile. In the
current glsa-check GUI this will make it impossible to determine whether
the system is still affected by the GLSA (e.g. by re-emerging, or when a
GLSA is changed afterwards).

The current place for the checkfile (/var/cache) is not persistent per
FHS, meaning that people might clean out the contents of their injected
GLSAs. Since glsa.py is moving to portage anyway, we can use
/var/lib/portage as a place to store the injected GLSAs. Documentation
has been updated accordingly.

Note that the old checkfile should not be moved to the previous location
on upgrade since this will cause false negatives due to the above
arguments. A message should appear on upgrade (pkg_postinst or similar).

svn path=/trunk/gentoolkit/; revision=649