Fix: CRYPTO_THREAD_run_once

InitOnceExecuteOnce returns nonzero on success:
MSDN: "If the function succeeds, the return value is nonzero."

So return 1 if it is nonzero, 0 others.
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>