ci: Move FDO_DISTRIBUTION_TAG assignment to template

This will be useful in more places later. Should have no functional
effect for now.

Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7988>

.gitlab-ci.yml

@@ -189,6 +189,14 @@ success:
       # https://gitlab.com/gitlab-org/gitlab-ce/commit/8788fb925706cad594adf6917a6c5f6587dd1521
       - artifacts
 
+
+# Docker image tag helper template
+
+.incorporate-templates-commit:
+  variables:
+    FDO_DISTRIBUTION_TAG: "${MESA_IMAGE_TAG}--${MESA_TEMPLATES_COMMIT}"
+
+
 # Build the CI docker images.
 #
 # MESA_IMAGE_TAG is the tag of the docker image used by later stage jobs. If the
@@ -210,6 +218,7 @@ success:
   stage: container
   extends:
     - .ci-run-policy
+    - .incorporate-templates-commit
   rules:
     - *ignore_scheduled_pipelines
     # Run pipeline by default in the main project if any CI pipeline
@@ -239,7 +248,6 @@ success:
     # Otherwise, container jobs won't run
     - when: never
   variables:
-    FDO_DISTRIBUTION_TAG: "${MESA_IMAGE_TAG}--${MESA_TEMPLATES_COMMIT}"
     FDO_DISTRIBUTION_VERSION: buster-slim
     FDO_REPO_SUFFIX: "debian/$CI_JOB_NAME"
     FDO_DISTRIBUTION_EXEC: 'env FDO_CI_CONCURRENT=${FDO_CI_CONCURRENT} bash .gitlab-ci/container/${CI_JOB_NAME}.sh'