xfsprogs: update 'make deb' to use tarball

xfsprogs: update 'make deb' to use tarball

This patch changes the build process so that 'make deb' uses the same
process of creating a source tree as the release script.

* Add a list of files which go in the release tarball in .gitcensus
  This is needed so that you can create a tarball in a bare release
  tree, when .git is not available.

* Modify the SRCTAR target to include files from .gitcensus and use tar
  instead of git archive.

* Modify the SRCTARINC files to include .gitcensus, and include
  .gitcensus in the 'make realclean' target.

* remove the 'make source-link' target.

Signed-off-by: Ben Myers <bpm@sgi.com>
Reviewed-by: Nathan Scott <nathans@debian.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>