Make -H 'Host: my-server' set Host Header on Requests

[ryohare]

Found myself needing to dirbust with a custom host header to hit the right vhost. Couldnt find it in the tool, so I figured I'd add it.

It the libgobuster http client is initialized with a host header, req.Host will be set from the header value stored in the struct.

Opened and issue for this: #271.

[firefart]

Hi @ryohare ,
thanks but this is wrongly implemented and will break VHOST mode. Currently there is the Host field on libgobuster.RequestOptions which should be passed from the single modes instead.

[firefart]

Ah sorry missed the exception, this should work. Will add a few modifications and comments to it, thanks!

[ryohare]

I saw the Host parameter being passed in for the VHost mode, so yeah, I added it as the else in the if. Parsed out the host in the constructor for minor perf increases.

One thing I considered but would defer to the team here was adding the host parameter as an argument, like user-agent is. Just went with it as a header to make it a less significant user facing change....