qemudDomainMigrateFinish2: handle a case of virDomainSaveStatus failure

* src/qemu/qemu_driver.c (qemudDomainMigrateFinish2): Don't ignore
virDomainSaveStatus failure.
* src/conf/domain_conf.h (virDomainSaveStatus): Use
ATTRIBUTE_RETURN_CHECK, so this doesn't happen again.

src/conf/domain_conf.h

@@ -1011,7 +1011,7 @@ int virDomainSaveConfig(const char *configDir,
                         virDomainDefPtr def);
 int virDomainSaveStatus(virCapsPtr caps,
                         const char *statusDir,
-                        virDomainObjPtr obj);
+                        virDomainObjPtr obj) ATTRIBUTE_RETURN_CHECK;
 
 typedef void (*virDomainLoadConfigNotify)(virDomainObjPtr dom,
                                           int newDomain,

src/qemu/qemu_driver.c

@@ -10816,7 +10816,10 @@ qemudDomainMigrateFinish2 (virConnectPtr dconn,
                                              VIR_DOMAIN_EVENT_SUSPENDED,
                                              VIR_DOMAIN_EVENT_SUSPENDED_PAUSED);
         }
-        virDomainSaveStatus(driver->caps, driver->stateDir, vm);
+        if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0) {
+            VIR_WARN("Failed to save status on vm %s", vm->def->name);
+            goto endjob;
+        }
     } else {
         qemudShutdownVMDaemon(driver, vm, 0);
         event = virDomainEventNewFromObj(vm,