src/kauth/krb_udp.c: Remove redundant NULL check for array address

src/kauth/krb_udp.c: Remove redundant NULL check for array address

Resolves this warning with clang:

krb_udp.c:302:13: warning: address of array 'tentry.misc_auth_bytes' will always evaluate to 'true' [-Wpointer-bool-conversion]
        if (tentry.misc_auth_bytes) {
        ~~  ~~~~~~~^~~~~~~~~~~~~~~

Reviewed-on: http://gerrit.openafs.org/11964
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 09bf3ebb26a3d8a4bd10571b394a59207a7f6980)

Change-Id: I94850d438902c358239142d696fae7206cef55a6
Reviewed-on: http://gerrit.openafs.org/12077
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>