builder/file: defer close after testing for errors
builder/file: defer close after testing for errors

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