Add explicit libafsauthent dependency for aklog

Add explicit libafsauthent dependency for aklog

Prevents occasional failures with parallel builds by ensuring
libafsauthent is built before aklog, which needs it.

Change-Id: Ibb0bdda3ce1fa306dfee1343e0b8b97486ee5efb
Reviewed-on: http://gerrit.openafs.org/3386
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Chaz Chandler <clc31@inbox.com>
Tested-by: Chaz Chandler <clc31@inbox.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>