Remove PipelineRun trigger type from back end code

The trigger field was removed in tektoncd/pipeline#857 and should
have been removed from the dashboard code in the intervening time.

pkg/endpoints/pipeline.go

@@ -252,7 +252,7 @@ func (r Resource) createPipelineRunImpl(pipelineRunData ManualPipelineRun, names
  }
 
  // PipelineRun yaml defines references to resources
- newPipelineRunData, err := definePipelineRun(generatedPipelineRunName, namespace, serviceAccount, pipelineRunData.REPOURL, pipeline, v1alpha1.PipelineTriggerTypeManual, resources, params)
+ newPipelineRunData, err := definePipelineRun(generatedPipelineRunName, namespace, serviceAccount, pipelineRunData.REPOURL, pipeline, resources, params)
  if err != nil {
  errorMsg := fmt.Sprintf("there was a problem defining the pipeline run: %s", err)
  logging.Log.Error(errorMsg)
@@ -357,7 +357,6 @@ func definePipelineResource(name, namespace string, params []v1alpha1.Param, res
 each PipelineRun has a 1 hour timeout: */
 func definePipelineRun(pipelineRunName, namespace, saName, repoUrl string,
  pipeline v1alpha1.Pipeline,
- triggerType v1alpha1.PipelineTriggerType,
  resourceBinding []v1alpha1.PipelineResourceBinding,
  params []v1alpha1.Param) (*v1alpha1.PipelineRun, error) {
 
@@ -385,8 +384,6 @@ func definePipelineRun(pipelineRunName, namespace, saName, repoUrl string,
 
  Spec: v1alpha1.PipelineRunSpec{
  PipelineRef: v1alpha1.PipelineRef{Name: pipeline.Name},
- // E.g. v1alpha1.PipelineTriggerTypeManual
- Trigger: v1alpha1.PipelineTrigger{Type: triggerType},
  ServiceAccount: saName,
  Timeout: &metav1.Duration{Duration: 1 * time.Hour},
  Resources: resourceBinding,
@@ -559,11 +556,6 @@ func (r Resource) rebuildRun(name, namespace string) (*v1alpha1.PipelineRun, err
  newPipelineRunData.Name = generateNewNameForRebuild(name)
  newPipelineRunData.ResourceVersion = ""
 
- // It's mandatory, so if it's not set already choose manual
- if newPipelineRunData.Spec.Trigger.Type == "" {
- newPipelineRunData.Spec.Trigger.Type = v1alpha1.PipelineTriggerTypeManual
- }
-
  currentLabels := pipelineRun.GetLabels()
 
  if currentLabels != nil {