Fix comments in linux-tools rules
Src pkg build fixes; un-hardcode directories

- Fix source pkg builds:
  - Only clean source package for those packages w/source config step;
    some packages don't like being cleaned, and those are pure anyway
  - Symlink Debian orig tarball from DISTDIR instead of PPADIR, where
    it may be missing after cleaning the package from the PPA
- Un-hardcode REPODIR, DISTDIR and MISCDIR
- Misc rearranging