tubik: Fix objdir builds

tubik: Fix objdir builds

 - Make netutils.c include afs/dirpath.h, so we don't have to find the
   correct include dir for "dirpath.h"

 - Fix dependencies in tvlserver, tbudb, and tptserver, and refer to
   sources in srcdir where appropriate

Change-Id: Id9c2b3eefaa9d02ccb197a61341776444b958cdc
Reviewed-on: http://gerrit.openafs.org/2521
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>