qemu: Tidy up job handling during live migration

qemu: Tidy up job handling during live migration

During a QEMU live migration several warning messages about job
handling could be written to syslog on the destination host:

"entering monitor without asking for a nested job is dangerous"

The messages are written because the job handling during migration
uses hard coded asyncJob values in several places that are incorrect.

This patch passes the required asyncJob value around and prevents
the warnings as well as any issues that the warnings may be referring
to.

https://bugzilla.redhat.com/show_bug.cgi?id=1130089

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>