fs/affs/super.c: bugfix / double free

Commit 842a859d ("affs: use ->kill_sb() to simplify ->put_super()
and failure exits of ->mount()") adds .kill_sb which frees sbi but
doesn't remove sbi free in case of parse_options error causing double
free+random crash.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>	[3.14.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/affs/super.c

@@ -340,8 +340,6 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent)
 				&blocksize,&sbi->s_prefix,
 				sbi->s_volume, &mount_flags)) {
 		printk(KERN_ERR "AFFS: Error parsing options\n");
-		kfree(sbi->s_prefix);
-		kfree(sbi);
 		return -EINVAL;
 	}
 	/* N.B. after this point s_prefix must be released */