Comment 3 for bug 770721

To ensure that package copies continue without interruption, and
without need for any time-dependent changes, like changing a crontab
at the same time that a Launchpad change is deployed, the plan is to
land four branches as follows:

1. To Launchpad: Make --exclude work with process-job-source-groups.py.

2. To Launchpad's crontabs: Change IPlainPackageCopyJobSource to run
   on ackee every minute and stop running it on loganberry. The latter
   will be done with --exclude.

3. To Launchpad: Change IPlainPackageCopyJobSource to be in the
   FREQUENT job source group.

4. To Launchpad's crontabs: Remove the --exclude from the crontab on
   loganberry.

Each branch needs to land and be deployed before the next can be
rolled through.