auth: plug auth realms memory leaks

auth: plug auth realms memory leaks

The function _afsconf_FreeRealms, called by afsconf_CloseInternal, leaks
two afsconf_realms structures.

The function _afsconf_LoadRealms also leaks those two structures when it
fails.

These memory leaks were discovered with valgrind.

Reviewed-on: https://gerrit.openafs.org/13395
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
(cherry picked from commit 80ed9d98779135d43f23c9e51e7bd6bce36405f1)

Change-Id: I3e4824e2be4a22b62c1e9502860b952db777cae7
Reviewed-on: https://gerrit.openafs.org/13900
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Yadavendra Yadav <yadayada@in.ibm.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>