NetDemo errors now only clear the gamestate and gameaction when in the middle of playing back a demo.

Fixes an issue where automatically attempting to record a netdemo to a non-existent directory gets Odamex stuck when connecting to a server, but this fix also targets a number of other undesirable behaviors as well.

git-svn-id: http://odamex.net/svn/root/trunk@3777 b0bcef46-2027-0410-bd56-ab726e9a1d04
Only unlatch serverinfo cvars when connected to a server.

Fixes bug 963.

git-svn-id: http://odamex.net/svn/root/trunk@3778 b0bcef46-2027-0410-bd56-ab726e9a1d04