#9777 breaks clients that build with disabled curve25519

#9777 (moved) made us try 32 times to get a circuit with at least one ntor supporting relay in it, and after that we give up.

But if you build without CURVE25519_ENABLED you're never going to get there.

Seems like we should allow people who build without it to work?

Suggested by https://blog.torproject.org/blog/tor-02422-released#comment-63335