RunWithUi sets appropriate default for stderr buffer
RunWithUi sets appropriate default for stderr buffer

- The WinRM communicator requires that stderr is not nil
- RunWithUi will set a default stderr buffer if none is specified in the command

rnaveiras/packer,ricardclau/packer,mitchellh/packer,pecigonzalo/packer,mitchellh/packer,rnaveiras/packer,pecigonzalo/packer,ricardclau/packer,hashicorp/packer,rnaveiras/packer,rnaveiras/packer,hashicorp/packer,rnaveiras/packer,pecigonzalo/packer,hashicorp/packer,ricardclau/packer,mitchellh/packer,ricardclau/packer,ricardclau/packer,pecigonzalo/packer,mitchellh/packer,rnaveiras/packer,hashicorp/packer,mitchellh/packer,ricardclau/packer