callRemote will always return a nil errno even if successful

[patrikjuvonen]

Describe the bug
callRemote returns a nil errno although the request was successful. This behavior is not consistent with fetchRemote.

To Reproduce

1. Send a request with callRemote.
2. Inspect the errno argument provided by the callback function.

Expected behavior
CURLE_OK (0) as the errno if the request went through okay (see error codes on Wiki). If the request did not go through alright then it should return the corresponding error code for that error.

MTA Client & Server:

• Multi Theft Auto v1.5.5-release-13959
• Windows 10.0.17134.165

Additional context
Initially committed here: #271 (comment)
Will create a new PR for this.

[jushar]

Can this be fixed without breaking backwards compatibility?

[patrikjuvonen]

If you prefer, we can use some sort of a version check, if that is okay to do?