Fixed issue when jpackage is not online

Added a cached mirror for the jpackage mirrors list on
resources.ovirt.org, it will get the official jpackage list if online,
and use a cached answer if not online, that avoids the failure when
jpackage site is down.

Change-Id: Idbc5cb9424c1448c9acfcead30b8ed68db3ea6b3
Signed-off-by: David Caro <dcaroest@redhat.com>