Add an absent job

Author: AA-Turner

salt/docs/init.sls

@@ -100,6 +100,12 @@ docsbuild-only-html:
         --select-output=only-html
     - user: docsbuild
     - minute: 16
+
+# Dummy so that the old cron jobs are stopped
+docsbuild-full:
+  cron.absent:
+    - identifier: docsbuild-full
+    - user: docsbuild
     - require:
       - cmd: virtualenv-dependencies