bozo: Constify bozo_Log 'format' argument

bozo: Constify bozo_Log 'format' argument

We clearly do not need to modify the format string; declare it const.
This makes the signature of bozo_Log identical to FSLog, which can
make it easier to use these functions interchangeably.

Reviewed-on: http://gerrit.openafs.org/10830
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit ed1b1df3c8acf9a2c5d4dface88ac15dcb8d7a2e)

Change-Id: I29fb3df82866dc8457d92a0b88eb02ae50879db7
Reviewed-on: http://gerrit.openafs.org/11931
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>