Running the BBR Scale job every 4 hours

Change-Id: I115452a8f5b6567c8e8d3747f5a9ee365e90e06e
diff --git a/jjb/bbr.yaml b/jjb/bbr.yaml
index 4ac6ce2..f5bd5c9 100644
--- a/jjb/bbr.yaml
+++ b/jjb/bbr.yaml
@@ -43,7 +43,7 @@
     triggers:
       - timed: |
           TZ=America/Los_Angeles
-          H * * * *
+          H H/4 * * *
 
     parameters:
       - string: