The function qemu_savevm_state_cancel is called after the migration
in migration_thread, it seems strange to 'cancel' it after completion,
rename it to qemu_savevm_state_cleanup looks better.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com&gt;al3>
Reviewed-by: Amit Shah <amit.shah@redhat.com&gt;al3>
Signed-off-by: Juan Quintela <quintela@redhat.com&gt;al3>