lxc: Fix virLXCDomainObjBeginJob position in lxcDomainSetMemoryParameters

Adjust the code to perform the virLXCDomainObjBeginJob first
and then the call virDomainLiveConfigHelperMethod.
As Ján Tomko pointed out, in virDomainLiveConfigHelperMethod,
there is a check to see if the domain is active when AFFECT_LIVE is set.
Since virLXCDomainObjBeginJob unlocks the virDomainObjPtr lock,
the domain could possibly be destroyed while we wait for the job
and the check results would no longer be valid.
Signed-off-by: NKaterina Koukiou <k.koukiou@gmail.com>

src/lxc/lxc_driver.c

@@ -840,14 +840,16 @@ lxcDomainSetMemoryParameters(virDomainPtr dom,
     cfg = virLXCDriverGetConfig(driver);
 
     if (virDomainSetMemoryParametersEnsureACL(dom->conn, vm->def, flags) < 0 ||
-        !(caps = virLXCDriverGetCapabilities(driver, false)) ||
-        virDomainLiveConfigHelperMethod(caps, driver->xmlopt,
-                                        vm, &flags, &vmdef) < 0)
+        !(caps = virLXCDriverGetCapabilities(driver, false)))
         goto cleanup;
 
     if (virLXCDomainObjBeginJob(driver, vm, LXC_JOB_MODIFY) < 0)
         goto cleanup;
 
+    if (virDomainLiveConfigHelperMethod(caps, driver->xmlopt,
+                                        vm, &flags, &vmdef) < 0)
+        goto endjob;
+
     if (flags & VIR_DOMAIN_AFFECT_LIVE &&
         !virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_MEMORY)) {
         virReportError(VIR_ERR_OPERATION_INVALID,