tubik: Link with libafsauthent

tubik: Link with libafsauthent

libubik_pthread.a requires libafsauthent.a, since we make use of
afsconf_* functions. Add libafsauthent to LIBS and make tubik depend
on it.

Remove linking to liblwp while we're here, as we should not be using
any LWP code.

Change-Id: Ie028fedfbc3e7a8a78dc69a2c38be99eb72602da
Reviewed-on: http://gerrit.openafs.org/3464
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>