Prototype ka_log

Prototype ka_log

Prototype ka_log in kauth/kalog.h to prevent warnings. While we're at
it, only prototype kalog_log and kalog_Init when they actually get
implemented.

Reviewed-on: http://gerrit.openafs.org/679
Reviewed-by: Simon Wilkinson <sxw@inf.ed.ac.uk>
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>