[PATCH] sched: remove stale version info from kernel/sched_debug.c

kernel/sched_debug.c referred to CFS -v20, but there's no CFS versioning
needed within the upstream kernel.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>