Prepare submodules on an explicit request

Change-Id: I060b2169d332e079d3b208c7cbfc53ffeb2769b4
diff --git a/zuul.yaml b/zuul.yaml
index c3077ab..1f186d0 100644
--- a/zuul.yaml
+++ b/zuul.yaml
@@ -5,3 +5,8 @@
     run: playbooks/run-test-command/run.yaml
     vars:
       test_command: "ci/build.sh"
+
+- job:
+    name: run-ci-build-sh-with-submodules
+    parent: run-ci-build-sh
+    pre-run: playbooks/git-submodules/run.yaml