sys-apps/policycoreutils: Depend on audit[python], fix selocal and fix build instruct...

sys-apps/policycoreutils: Depend on audit[python], fix selocal and fix build instructions for 2.6 and higher

The live ebuild reflects the latest state of the user space project of SELinux.
In the release of 2.6, a number of changes to the 2.6 ebuild were made but not
pushed to the live ebuild, so we did that.

Alongside, we also fixed the following bugs:
- Bug 605692 fixes the audit dependency - we already depended on audit if
  USE=audit was set, but we did not force the use of the python USE flag
  if we did, which is a requirement
  (note that this bug is partially fixed by this, another change is still
  pending).
- Bug 597978 fixes the selocal command, which failed to obtain attribute
  and other information since the setools 4 release

Package-Manager: portage-2.3.0