Don't imply that setting the boot_ variables to "NO" will disable them.

MFC after:	3 days

sys/boot/forth/loader.conf

@@ -58,12 +58,14 @@ module_path="/boot/kernel;/boot/modules;/modules"	# Set the module search path
 ###  Kernel settings  ########################################
 ##############################################################
 
-#boot_askname="NO"	# Prompt the user for the name of the root device
-#boot_ddb="NO"		# Instructs the kernel to start in the DDB debugger
-#boot_gdb="NO"		# Selects gdb-remote mode for the kernel debugger
-#boot_single="NO"	# Start system in single-user mode
-#boot_userconfig="NO"	# Run kernel's interactive device configuration program
-#boot_verbose="NO"	# Causes extra debugging information to be printed
+			# The following boot_ variables are enabled
+			# by setting them to any value.
+#boot_askname=""	# Prompt the user for the name of the root device
+#boot_ddb=""		# Instructs the kernel to start in the DDB debugger
+#boot_gdb=""		# Selects gdb-remote mode for the kernel debugger
+#boot_single=""		# Start system in single-user mode
+#boot_userconfig=""	# Run kernel's interactive device configuration program
+#boot_verbose=""	# Causes extra debugging information to be printed
 #init_path="/sbin/init:/sbin/oinit:/sbin/init.bak:/stand/sysinstall"
 			# Sets the list of init candidates
 #dumpdev="ad0s1b"	# Set device for crash dumps