Add ddb.log example; OK halex@

src/etc/examples/sysctl.conf

@@ -1,4 +1,4 @@
-#	$OpenBSD: sysctl.conf,v 1.3 2014/08/27 14:04:15 florian Exp $
+#	$OpenBSD: sysctl.conf,v 1.4 2015/04/03 15:50:28 millert Exp $
 #
 # This file contains a list of sysctl options the user wants set at
 # boot time.  See sysctl(3) and sysctl(8) for more information on
@@ -24,6 +24,7 @@
 #net.pipex.enable=1		# 1=Enable pipex(4) for npppd(8)
 #ddb.panic=0			# 0=Do not drop into ddb on a kernel panic
 #ddb.console=1			# 1=Permit entry of ddb from the console
+#ddb.log=1			# 1=Log ddb output in kernel message buffer
 #fs.posix.setuid=0		# 0=Traditional BSD chown() semantics
 #vm.swapencrypt.enable=0	# 0=Do not encrypt pages that go to swap
 #vfs.nfs.iothreads=4		# Number of nfsio kernel threads