Description of problem: satellite-sync's caching isn't versioned. This causes an
issue where we have to manually remove the cache when the cache format changes.
What really needs to happen is that satellite-sync will detect when the version
of the cache changes and will automatically replace the cache as needed. This
will enable us to simplify the upgrade process a little bit.


Version-Release number of selected component (if applicable): All of them.


How reproducible: Always


Steps to Reproduce:
1. Upgrade rhns-server on a satellite.
2. ls -l /var/cache/rhn/
  
Actual results: /var/cache/rhn/ is wiped out.


Expected results: We should only wipe out /var/cache/rhn/ when the format of the
cache changes.


Additional info: I used capslock and multiple exclamation points just like I
said I would in IRC. :)