[Libvirt-cim] [PATCH 0 of 2] Add migration job support

This set adds job support to migration, so that the migration methods return immediately with a job reference. The progress of the migration can be monitored by looking at Virt_MigrationJob instances. I left a good opening for indications (which will be necessary) by adding the migrate_job_set_state() function. This updates the state of the persistent job, which would be time(s) when we're looking to send an indication. Right now, Jobs are left in the persistent store after they're complete. Comments about the best policy for handling this are welcome. I know that I should be able to put a lifetime on them so they expire after completion, but I'm not sure if that's something that should be left to the client.