Skip base build if provide image id

.gitlab-ci.yml

@@ -104,6 +104,10 @@ build_base_image:
   tags:
     - build
   script:
+    - |
+      if [ -n "${BUILT_BASE_IMAGE_ID}" ]; then
+        exit 0
+      fi
     - *get_build_date
     - export REPO_HEAD=$(git rev-parse --short HEAD)
     - export PKR_VAR_flavor="m1.medium"