autofs: remove ino free in autofs4_dir_symlink()

The inode allocation failure case in autofs4_dir_symlink() frees the
autofs dentry info of the dentry without setting ->d_fsdata to NULL.

That could lead to a double free so just get rid of the free and leave it
to ->d_release().

Link: http://lkml.kernel.org/r/20160812024759.12352.10653.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs4/root.c

@@ -577,8 +577,6 @@ static int autofs4_dir_symlink(struct inode *dir,
 	inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555);
 	if (!inode) {
 		kfree(cp);
-		if (!dentry->d_fsdata)
-			kfree(ino);
 		return -ENOMEM;
 	}
 	inode->i_private = cp;