This reverts commit 8607f524, reversing
changes made to 11d76a65.

The code in i_net.c doesn't actually seem to be used in SRB2. I was able to compile a build without it, and hosting and joining netgames worked just fine (well, as fine as they can with the current state of the netcode...).

Do we really need to keep it around? If not, I say get rid of it. It seems like useless clutter that is just going to confuse people who are trying to understand the source code.