Add branch name and remove triggers in metal3 container image build job

Change-Id: I6dd2900fb2e924e28b798ad55d5717b8097984ba
diff --git a/jjb/metal3/job_container_image_building.yaml b/jjb/metal3/job_container_image_building.yaml
index 9ab8cfc..989351f 100644
--- a/jjb/metal3/job_container_image_building.yaml
+++ b/jjb/metal3/job_container_image_building.yaml
@@ -27,7 +27,7 @@
 - job-template:
     id: container_image_building
     name: '{job_prefix}_{image_name}_container_image_building'
-    description: "Builder job for container images for Metal3 CI"
+    description: 'Builder job for {image_name} container image for Metal3'
     project-type: pipeline
     defaults: global
     disabled: False
@@ -35,8 +35,12 @@
     parameters:
     - string:
         name: BUILD_CONTAINER_IMAGE_NAME
-        default: '${image_name}'
+        default: '{image_name}'
         description: 'Name of the container image to build'
+    - string:
+        name: BUILD_CONTAINER_IMAGE_BRANCH
+        default: 'main'
+        description: 'Target branch of the build'
 
     properties:
     - build-discarder:
@@ -47,9 +51,7 @@
     - github:
         url: '{repo}'
 
-    triggers:
-      - github
-
+    # No triggers. This job will be triggered by github actions
     pipeline-scm:
       scm:
       - git: