Delete dead CLUSTERDEBUG config option.

Reviewed by:	mckusick
Tested by:	pho
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D28679

sys/conf/NOTES

@@ -2732,9 +2732,6 @@ options 	NSWBUF_MIN=120
 
 options 	CAM_DEBUG_DELAY
 
-# VFS cluster debugging.
-options 	CLUSTERDEBUG
-
 options 	DEBUG
 
 # Kernel filelock debugging.

sys/conf/options

@@ -570,7 +570,6 @@ TI_JUMBO_HDRSPLIT	opt_ti.h
 # Misc debug flags.  Most of these should probably be replaced with
 # 'DEBUG', and then let people recompile just the interesting modules
 # with 'make CC="cc -DDEBUG"'.
-CLUSTERDEBUG		opt_debug_cluster.h
 DEBUG_1284		opt_ppb_1284.h
 LPT_DEBUG		opt_lpt.h
 PLIP_DEBUG		opt_plip.h

sys/kern/vfs_cluster.c

@@ -36,8 +36,6 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include "opt_debug_cluster.h"
-
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
@@ -56,12 +54,6 @@ __FBSDID("$FreeBSD$");
 #include <vm/vm_page.h>
 #include <sys/sysctl.h>
 
-#if defined(CLUSTERDEBUG)
-static int	rcluster= 0;
-SYSCTL_INT(_debug, OID_AUTO, rcluster, CTLFLAG_RW, &rcluster, 0,
-    "Debug VFS clustering code");
-#endif
-
 static MALLOC_DEFINE(M_SEGMENT, "cl_savebuf", "cluster_save buffer");
 static uma_zone_t cluster_pbuf_zone;