sodium_init() will return 0 on success, -1 on failure, and 1 if sodium is
already loaded and initialized (which is not an error). In the case
where libsodium is already initialized and the system is restarted we
may return 1 from onload nif function resulting in a crash.
- change the call to sodium_init() to check for an error return (-1) and
return -1 explicitly in this case, otherwise always return zero at the
end of our onload function.
Bryan Paxton
e18f9b7337