libafsauthent: Add volser and vldb

libafsauthent: Add volser and vldb

Add the volser and vldb families of functions to libafsauthent. This
allows applications such as perl-AFS which are building pthreaded
clients to use a single library, rather than trying to mix LWP and
pthreaded code within the same process.

Reviewed-on: http://gerrit.openafs.org/5157
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
(cherry picked from commit 55beacdc385424770c78cf055e8fd426075506f1)

Change-Id: I60a35b3032f071a0a3ef4dc66221f22166942bfd
Reviewed-on: http://gerrit.openafs.org/8799
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>