usage.c: remove reference to busybox.h
*: s/include "busybox.h"/include "libbb.h"

diff --git a/util-linux/freeramdisk.c b/util-linux/freeramdisk.c
index ae341b0..a1f2c56 100644
--- a/util-linux/freeramdisk.c
+++ b/util-linux/freeramdisk.c
@@ -9,7 +9,7 @@
  * Licensed under GPLv2, see file LICENSE in this tarball for details.
  */
 
-#include "busybox.h"
+#include "libbb.h"
 
 /* From <linux/fd.h> */
 #define FDFLUSH  _IO(2,0x4b)