ci-dockerfiles-sanity-check: Add params to allow build job manually

Not just via a Gerrit trigger. This is required for comfortable debugging.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I966ac899ef09da67a45279d13b4761d6bb8755e5
diff --git a/ci-dockerfiles-sanity-check.yaml b/ci-dockerfiles-sanity-check.yaml
index 1daa200..5bf00ee 100644
--- a/ci-dockerfiles-sanity-check.yaml
+++ b/ci-dockerfiles-sanity-check.yaml
@@ -24,6 +24,19 @@
     display-name: 'CI Dockerfiles sanity check'
     parameters:
         - string:
+            name: GERRIT_PROJECT
+            default: 'ci/dockerfiles'
+            description: |
+              Git project to build (also set by Gerrit trigger)
+        - string:
+            name: GERRIT_BRANCH
+            default: 'master'
+            description: |
+              Git branch to build (also set by Gerrit trigger)
+        - string:
+            name: GERRIT_REFSPEC
+            default: ''
+        - string:
             name: DOCKER_SUFFIX
             default: '-check'
             description: |