LU-1199 lbuild: Remove obsolete CVS functionality

Remove code from lbuild that is obsolete now that CVS is no longer
used by the Lustre project.  The following three command line
parameters are no longer used:

  -d
  --disable-datestamp
  --tag

The former two were removed completely.  The --tag remains, but
is now ignored by lbuild (except that is prints a warning about
the option being deprecated).   We need to allow --tag for now
to accomodate the Intel build farm which always passes in the
bogus option "--tag foo".

Change-Id: I68636f599937cec2ea9298a395df0c875762215e
Signed-off-by: Christopher J. Morrone <morrone2@llnl.gov>
LU-1199 lbuild: Clean up path canonicalization

Simplify the canonicalization of paths through the use of readlink.

Change-Id: I51682f78b76efd790ac3829059de1f1f8702fe23
Signed-off-by: Christopher J. Morrone <morrone2@llnl.gov>