bozo: Declare tweak_config() void

The AIX-specific tweak_config() clearly doesn't return a value, so
don't say it does.

Change-Id: I8b4535427438cb05c4243b4ef2a875c685c7bb76
Reviewed-on: https://gerrit.openafs.org/15434
Reviewed-by: Ben Huntsman <ben@huntsmans.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>

src/bozo/bosserver.c

@@ -634,7 +634,7 @@ BozoDaemon(void *unused)
 }
 
 #ifdef AFS_AIX32_ENV
-static int
+static void
 tweak_config(void)
 {
     FILE *f;