qemu: save domain status after set the blkio parameters

After set the blkio parameters for running domain, save the change into
live xml is needed to survive restarting the libvirtd, same story with
bug 1146511, meanwhile add call qemuDomainObjBeginJob/qemuDomainObjEndJob
in qemuDomainSetBlkioParameters
Signed-off-by: NShanzhi Yu <shyu@redhat.com>

src/qemu/qemu_driver.c

@@ -8097,15 +8097,18 @@ qemuDomainSetBlkioParameters(virDomainPtr dom,
     if (!(caps = virQEMUDriverGetCapabilities(driver, false)))
         goto cleanup;
 
+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
+        goto cleanup;
+
     if (virDomainLiveConfigHelperMethod(caps, driver->xmlopt, vm, &flags,
                                         &persistentDef) < 0)
-        goto cleanup;
+        goto endjob;
 
     if (flags & VIR_DOMAIN_AFFECT_LIVE) {
         if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_BLKIO)) {
             virReportError(VIR_ERR_OPERATION_INVALID, "%s",
                            _("blkio cgroup isn't mounted"));
-            goto cleanup;
+            goto endjob;
         }
     }
 
@@ -8198,9 +8201,12 @@ qemuDomainSetBlkioParameters(virDomainPtr dom,
                 VIR_FREE(devices);
             }
         }
+
+        if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0)
+            goto endjob;
     }
     if (ret < 0)
-        goto cleanup;
+        goto endjob;
     if (flags & VIR_DOMAIN_AFFECT_CONFIG) {
         /* Clang can't see that if we get here, persistentDef was set.  */
         sa_assert(persistentDef);
@@ -8238,6 +8244,10 @@ qemuDomainSetBlkioParameters(virDomainPtr dom,
             ret = -1;
     }
 
+ endjob:
+    if (!qemuDomainObjEndJob(driver, vm))
+        vm = NULL;
+
  cleanup:
     if (vm)
         virObjectUnlock(vm);