socks: socks4 fix host resolve regression

1. The socks4 state machine was broken in the host resolving phase

2. The code now insists on IPv4-only when using SOCKS4 as the protocol
only supports that.

Regression from #4907 and 4a4b63da, shipped in 7.69.0

Reported-by: amishmm on github
Bug: https://github.com/curl/curl/issues/5053#issuecomment-596191594