LXC: show used memory as 0 when domain is not active

Before:
virsh # dominfo chx3
State:          shut off
Max memory:     92160 KiB
Used memory:    92160 KiB

After:
virsh # dominfo container1
State:          shut off
Max memory:     92160 KiB
Used memory:    0 KiB

Similar to qemu cases.
Signed-off-by: NChen Hanxiao <chenhanxiao@cn.fujitsu.com>

src/lxc/lxc_driver.c

@@ -584,7 +584,7 @@ static int lxcDomainGetInfo(virDomainPtr dom,
 
     if (!virDomainObjIsActive(vm)) {
         info->cpuTime = 0;
-        info->memory = vm->def->mem.cur_balloon;
+        info->memory = 0;
     } else {
         if (virCgroupGetCpuacctUsage(priv->cgroup, &(info->cpuTime)) < 0) {
             virReportError(VIR_ERR_OPERATION_FAILED,

src/qemu/qemu_driver.c

@@ -2534,7 +2534,7 @@ static int qemuDomainGetInfo(virDomainPtr dom,
             info->memory = vm->def->mem.cur_balloon;
         }
     } else {
-        info->memory = vm->def->mem.cur_balloon;
+        info->memory = 0;
     }
 
     info->nrVirtCpu = vm->def->vcpus;