libadmin: add header file deps

Add the missing header file dependencies to the library targets.
This is needed for parallel make.

Reviewed-on: http://gerrit.openafs.org/10726
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
(cherry picked from commit d2084563648cc1e8ec697c61f593935a0b5804a3)

Change-Id: I47b3b184a3284b56c4047e27b58b6cb3a8e16cef
Reviewed-on: http://gerrit.openafs.org/11235
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>