Missing 'const' from reiserfs MIN_KEY declaration.

In stree.c, MIN_KEY is declared const. The extern declaration in dir.c
doesn't match...
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/dir.c

@@ -10,7 +10,7 @@
 #include <linux/buffer_head.h>
 #include <asm/uaccess.h>
 
-extern struct reiserfs_key MIN_KEY;
+extern const struct reiserfs_key MIN_KEY;
 
 static int reiserfs_readdir(struct file *, void *, filldir_t);
 static int reiserfs_dir_fsync(struct file *filp, struct dentry *dentry,