kernfs: deal with kernfs_fill_super() failures

make sure that info->node is initialized early, so that kernfs_kill_sb()
can list_del() it safely.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/kernfs/mount.c

@@ -316,6 +316,7 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
 
 	info->root = root;
 	info->ns = ns;
+	INIT_LIST_HEAD(&info->node);
 
 	sb = sget_userns(fs_type, kernfs_test_super, kernfs_set_super, flags,
 			 &init_user_ns, info);