Add `make lint` target and fix errors that were found

Change-Id: Ibb2886d07e0e1c8a4b8928721a12eb94c01178a0
diff --git a/jjb/cord-macros.yaml b/jjb/cord-macros.yaml
index 8e43216..c287aab 100644
--- a/jjb/cord-macros.yaml
+++ b/jjb/cord-macros.yaml
@@ -69,7 +69,7 @@
       - gerrit:
           server-name: '{gerrit-server-name}'
           dependency-jobs: '{dependency-jobs}'
-          silent-start: True
+          silent-start: true
           trigger-on:
             - change-merged-event
           projects: