sendmail: specifying alternate port

[Vladimir Dronnikov]

> Busybox 1.12.2 sendmail has port 25 hardcoded and does not parse the port specified in the -H option.  The attached patch adds parsing the port from the -H option (if specified); otherwise, defaults to port 25.

I believe create_and_connect_stream_or_die() itself does port parsing.
That is, you can specify user:pass at smtp.net:2222 and it will
automagically connect to port 2222. So this part of the patch is
redundant.

>
> Also, sendmail was using the data from the -f option when checking the 250 response.  I believe this should be the server specified in the -H option.
>

-f specifies reply address and is required. -H, being optional, can be
missed; thus to achieve consistent behavior we should resort on -f
option. Moreover, -H takes  user:pass at server:port format, which can be
invalid for EHLO.

Thanks,
--
Vladimir