Merge pull request #228 from markpeek/markpeek-images

builder/amazon/common: handle missing source AMI error

builder/amazon/common/step_run_source_instance.go

@@ -41,6 +41,10 @@ func (s *StepRunSourceInstance) Run(state map[string]interface{}) multistep.Step
 		state["error"] = fmt.Errorf("There was a problem with the source AMI: %s", err)
 		return multistep.ActionHalt
 	}
+	if len(imageResp.Images) != 1 {
+		state["error"] = fmt.Errorf("The source AMI '%s' could not be found.", s.SourceAMI)
+		return multistep.ActionHalt
+	}
 
 	if s.ExpectedRootDevice != "" && imageResp.Images[0].RootDeviceType != s.ExpectedRootDevice {
 		state["error"] = fmt.Errorf(