Add missing va_end

Add missing va_end

Per man va_start:
Each invocation of va_start() must be matched by a corresponding
invocation of va_end() in the same function.

Reviewed-on: https://gerrit.openafs.org/13087
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 2b08d687b992f238fa59773ef2ff1710c520f861)

Change-Id: I8d649b06a8e0baedc40612fe7b2251df1426ce26
Reviewed-on: https://gerrit.openafs.org/13151
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: PatRiehecky <jcpunk@gmail.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>