Merge: Better error handling in Socket

Errors on both finding a host by its name and on connection are reported with all available details as an `Error`.

Pull-Request: #1428
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>
Reviewed-by: Jean Privat <jean@pryen.org>