libafsauthent: export additional xdr_ functions

libafsauthent: export additional xdr_ functions

Formally, we need to use xdr_free to deallocate storage for RPC output
variables, in case the XDR stack uses a different allocator than the
standard application allocator.  Some types have non-autogenerated
wrappers exposed already (e.g., token_FreeSet()), but for a handful of
the base ptint types we need to expose the xdr routines in order for a
safe way to deallocate their storage to be available.

Reviewed-on: https://gerrit.openafs.org/13131
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit c12cfd7331727142cb928e08ec32a708d0cfd1e9)

Change-Id: Iea3b0bd9fdb373020b41c2bcbf1ebbde222114a8
Reviewed-on: https://gerrit.openafs.org/13192
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Joe Gorse <jhgorse@gmail.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>