autofs4 - fix d_manage() return on rcu-walk

The daemon never needs to block and, in the rcu-walk case an error
return isn't used, so always return zero.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/autofs4/root.c

@@ -444,6 +444,8 @@ int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
 
 	/* The daemon never waits. */
 	if (autofs4_oz_mode(sbi)) {
+		if (rcu_walk)
+			return 0;
 		if (!d_mountpoint(dentry))
 			return -EISDIR;
 		return 0;