qemu: Send migrate_cancel when aborting migration
qemu: Send migrate_cancel when aborting migration

When QEMU reports failed or cancelled migration, we don't need to send
it migrate_cancel QMP command. But in all other error paths, such as if
we detect broken connection to a destination daemon or something else
happens inside libvirt, we need to explicitly send migrate_cancel
command instead of relying on the migration to be implicitly cancelled
when destination QEMU is killed.

Because we were not doing so, one could end up with a paused domain
after failed migration.

https://bugzilla.redhat.com/show_bug.cgi?id=1098833
https://bugzilla.redhat.com/show_bug.cgi?id=1100642

(cherry picked from commit e27d28970fb1eaaa3c34f75081bf3ca706abacda)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

Conflicts:
	src/qemu/qemu_migration.c -- both cleanup and cancel labels were
	    still unindented in RHEL-6

(cherry picked from 6.6 commit fe083529fde58cc9fcdcd3983ae25c3e7aee6cd1)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

Conflicts:
	src/qemu/qemu_migration.c -- commit 837154a not backported

mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2