Description of problem:
virsh dominfo can't get a correct VCPU number. The issue originally is met by users, who are using Openstack and Libvirt/LXC as their virtualization endpoint.


Version-Release number of selected component (if applicable):
# rpm -q libvirt
libvirt-0.9.10-16.el6.x86_64

How reproducible:
always

Steps to Reproduce:

# virsh -c lxc:/// define /tmp/toy.xml
Domain toy defined from /tmp/toy.xml

# virsh -c lxc:/// dumpxml toy
<domain type='lxc'>
  <name>toy</name>
  <uuid>bb428983-cb9f-4702-0f8d-7d4e143d9aad</uuid>
  <memory unit='KiB'>500000</memory>
  <currentMemory unit='KiB'>500000</currentMemory>
  <vcpu>4</vcpu>
  <os>
    <type arch='x86_64'>exe</type>
    <init>/bin/sh</init>
  </os>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/libvirt_lxc</emulator>
    <console type='pty'>
      <target type='lxc' port='0'/>
    </console>
  </devices>
</domain>

Notes, defined a lxc guest with 4 vcpu.

# virsh -c lxc:/// dominfo toy
Id:             -
Name:           toy
UUID:           bb428983-cb9f-4702-0f8d-7d4e143d9aad
OS Type:        exe
State:          shut off
CPU(s):         1
Max memory:     500000 kB
Used memory:    500000 kB
Persistent:     yes
Autostart:      disable
Managed save:   unknown
Security model: selinux
Security DOI:   0

Notes, virsh dominfo says the guest has only 1 vcpu.

Actual results:
The result is not consistent with actual vcpu number.

Expected results:
Fix it.

Additional info:
It's fine for qemu driver.