qemu builder now needs to explicitly set WinRMPort for StepConnect

Same as vbox builders, aligns qemu with changes to
helper/communicator/step_connect.go introduced by PR #2576

builder/qemu/builder.go

@@ -398,6 +398,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 				Host:      commHost,
 				SSHConfig: sshConfig,
 				SSHPort:   commPort,
+				WinRMPort: commPort,
 			},
 		)
 	}