Add s.SSHPort variable as the port WinRM uses to connect. This is needed on...

Add s.SSHPort variable as the port WinRM uses to connect. This is needed on any builder where the port used to connect is not the guest winrm port but a nated port on the host.
Similar behavior is used by the SSH communicator.

helper/communicator/step_connect.go

@@ -53,6 +53,7 @@ func (s *StepConnect) Run(state multistep.StateBag) multistep.StepAction {
 			Config:      s.Config,
 			Host:        s.Host,
 			WinRMConfig: s.WinRMConfig,
+			WinRMPort:   s.SSHPort,
 		},
 	}
 	for k, v := range s.CustomConnect {

helper/communicator/step_connect_winrm.go

@@ -25,6 +25,7 @@ type StepConnectWinRM struct {
 	Config      *Config
 	Host        func(multistep.StateBag) (string, error)
 	WinRMConfig func(multistep.StateBag) (*WinRMConfig, error)
+	WinRMPort   func(multistep.StateBag) (int, error)
 }
 
 func (s *StepConnectWinRM) Run(state multistep.StateBag) multistep.StepAction {
@@ -96,6 +97,13 @@ func (s *StepConnectWinRM) waitForWinRM(state multistep.StateBag, cancel <-chan
 			continue
 		}
 		port := s.Config.WinRMPort
+		if s.WinRMPort != nil {
+			port, err = s.WinRMPort(state)
+			if err != nil {
+				log.Printf("[DEBUG] Error getting WinRM port: %s", err)
+				continue
+			}
+		}
 
 		user := s.Config.WinRMUser
 		password := s.Config.WinRMPassword