remove wininet workaround in meterpreter http/s

We had a workaround to close connections on very old wininet implementations
that would not do it themselves. With the new WinHttp API-using meterpreters
and stagers, we no longer should use this workaround. It can actually be
actively bad and prematurely close the connection.

This needs testing around different payloads, and they should be on real
networks, ideally where TCP really has to work to get data transfered.

Author: Brent Cook

lib/rex/post/meterpreter/packet_dispatcher.rb

@@ -114,9 +114,6 @@ def on_passive_request(cli, req)
       cli.send_response(resp)
     end
 
-    # Force a closure for older WinInet implementations
-    self.passive_service.close_client( cli )
-
     rescue ::Exception => e
       elog("Exception handling request: #{cli.inspect} #{req.inspect} #{e.class} #{e} #{e.backtrace}")
     end