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

[Dan Smith]

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.