mirror-update: fix cron path

We have not put /usr/local/bin into the cron path, so it does not find
the update scripts.  Since the scripts were working with this path on
the old host, restore it as a cron variable to maintain the status
quo.

Change-Id: Id9b7533720d3ccd9251055dec5b452cf5963dc85

playbooks/roles/mirror-update/tasks/main.yaml

@@ -21,6 +21,12 @@
     group: root
     mode: '0400'
 
+- name: Set PATH for cron
+  cron:
+    name: PATH
+    env: yes
+    value: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+
 - name: Setup rsync mirror scripts
   include_tasks: rsync.yaml