Define cron to build com/log weekly

This adds a weekly schedule to the docker-merge job that builds
the library and pushes to the PackageCloud staging repo.

Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: Icd3f143df01f6eb43f95bf8cb77186a05a6535ab
diff --git a/jjb/com-log/com-log.yaml b/jjb/com-log/com-log.yaml
index 7fac3c7..0c8d339 100644
--- a/jjb/com-log/com-log.yaml
+++ b/jjb/com-log/com-log.yaml
@@ -34,7 +34,9 @@
     container-tag-method: latest
     jobs:
       - gerrit-docker-verify
-      - oran-gerrit-docker-ci-pc-merge
+      - oran-gerrit-docker-ci-pc-merge:
+          # stage every Saturday
+          cron: 'H H * * 6'
     stream:
       - master:
           branch: master