msdos_rmdir(): kill BS comment

it hadn't been checking for "busy" since 2.3.99-something and removing
that leaves us with "check if it's empty" followed by call of fat_dir_emtpy()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/fat/namei_msdos.c

@@ -314,10 +314,6 @@ static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
 	int err;
 
 	mutex_lock(&MSDOS_SB(sb)->s_lock);
-	/*
-	 * Check whether the directory is not in use, then check
-	 * whether it is empty.
-	 */
 	err = fat_dir_empty(inode);
 	if (err)
 		goto out;