aklog: Fix allow_weak_crypto warning

It's _crypto, not _enctypes. The user will just be more confused than
before if we tell them to do the wrong thing.

Reviewed-on: http://gerrit.openafs.org/8938
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>
Reviewed-by: Simon Wilkinson <simonxwilkinson@gmail.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
(cherry picked from commit f6f145c90fbc236c350ddaa4d18b359be581496f)

Change-Id: I17978b15f140729760ce84f1a7af913eac97d836
Reviewed-on: http://gerrit.openafs.org/8940
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>