Allow setting migration max downtime any time

This removes the artificial and unnecessary restriction that
virDomainSetMaxDowntime() only be called while a migration is in
progress.

https://bugzilla.redhat.com/show_bug.cgi?id=1146618Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_driver.c

@@ -12023,12 +12023,6 @@ qemuDomainMigrateSetMaxDowntime(virDomainPtr dom,
 
     priv = vm->privateData;
 
-    if (priv->job.asyncJob != QEMU_ASYNC_JOB_MIGRATION_OUT) {
-        virReportError(VIR_ERR_OPERATION_INVALID,
-                       "%s", _("domain is not being migrated"));
-        goto endjob;
-    }
-
     VIR_DEBUG("Setting migration downtime to %llums", downtime);
     qemuDomainObjEnterMonitor(driver, vm);
     ret = qemuMonitorSetMigrationDowntime(priv->mon, downtime);