common shell provisioner: define a ValidExitCode func
common shell provisioner: define a ValidExitCode func

ricardclau/packer,tas50/packer,tas50/packer,tas50/packer,paulmey/packer,bryson/packer,hashicorp/packer,grubernaut/packer,hashicorp/packer,bryson/packer,rnaveiras/packer,ricardclau/packer,rnaveiras/packer,bryson/packer,rnaveiras/packer,grubernaut/packer,mitchellh/packer,grubernaut/packer,grubernaut/packer,paulmey/packer,timsutton/packer,dave2/packer,pecigonzalo/packer,rnaveiras/packer,paulmey/packer,ricardclau/packer,tas50/packer,timsutton/packer,pecigonzalo/packer,rnaveiras/packer,ricardclau/packer,mitchellh/packer,tas50/packer,grubernaut/packer,paulmey/packer,rnaveiras/packer,dave2/packer,mitchellh/packer,timsutton/packer,hashicorp/packer,timsutton/packer,mitchellh/packer,dave2/packer,ricardclau/packer,bryson/packer,pecigonzalo/packer,ricardclau/packer,hashicorp/packer,grubernaut/packer,dave2/packer,tas50/packer,paulmey/packer,timsutton/packer,bryson/packer,dave2/packer,dave2/packer,bryson/packer,paulmey/packer,timsutton/packer,pecigonzalo/packer,mitchellh/packer