func (c *CreateMachineImages) populate(ctx context.Context, s *Step) DError {
	var errs DError
	for _, mi := range *c {
		errs = addErrs(errs, mi.populate(ctx, s))
	}
	return errs
}
populate pre-processed fields: Name, Project, Description and daisyName.
- sets defaults
- extends short partial URLs to include "projects/<project>"
package daisy
import (
	"context"
	"sync"
	"google.golang.org/api/googleapi"
)
type CreateMachineImages []*MachineImage