Explicitly exit with success

MFC after:	3 days
X-MFC-to:	stable/10

usr.sbin/bsdinstall/scripts/keymap

@@ -1,7 +1,7 @@
 #!/bin/sh
 #-
 # Copyright (c) 2011 Nathan Whitehorn
-# Copyright (c) 2013 Devin Teske
+# Copyright (c) 2013-2015 Devin Teske
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -231,6 +231,7 @@ while :; do
 done
 
 f_quietly f_keymap_kbdcontrol "$keymap"
+exit $SUCCESS
 
 ################################################################################
 # END