aklog: Return token when performing 524 conversion

aklog: Return token when performing 524 conversion

We weren't actually returning a token and username from
rxkad_get_converted_token. Do so.

This is a 1.6-specific change. This issue was fixed on master when
aklog was changed to use the new SetTokenEx family of pioctls in
commit 53837416cbed3ba4d11f63015e1f13800519f2ed.

Change-Id: I7395034c5225ca62b562ea39bd01762c74090b03
Reviewed-on: http://gerrit.openafs.org/4518
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Reviewed-by: Derrick Brashear <shadow@dementia.org>