wintest Improve wintest's handling of IP addresses and add more auto-setup

wintest Improve wintest's handling of IP addresses and add more auto-setup

 - Don't change the IP address if DHCP is not in use

   The main reason to 'fix' the IP is to get around Dynamic DNS issues caused
   by the DHCP server, if the VM is already on a fixed IP, it does not matter.

 - Set the maximum telnet connection limit to 1024

   This ensures that we can always make a new connection, regardless
   of the existing configuration.  We also catch more conditions when
   the server has restricted the number of connections, and try again.

 - Set the route after the connection drops out

   My WinXP box always wants to drop the default route

 - Set the DNS as a distinct step

   My WinXP box drops the connection when we set DNS servers

Andrew Bartlett