In fact, this is in RHEL for a while (since libvirt-0.9.11-rc1). Hence moving to POST:

commit 10a8b1f9585d7414d6d3a2571fffc5d699c4576b
Author:     Daniel P. Berrange <berrange>
AuthorDate: Wed Jan 18 11:38:49 2012 +0000
Commit:     Daniel P. Berrange <berrange>
CommitDate: Thu Mar 15 17:00:39 2012 +0000

    Add support for forcing a private network namespace for LXC guests
    
    If no <interface> elements are included in an LXC guest XML
    description, then the LXC guest will just see the host's
    network interfaces. It is desirable to be able to hide the
    host interfaces, without having to define any guest interfaces.
    
    This patch introduces a new feature flag <privnet/> to allow
    forcing of a private network namespace for LXC. In the future
    I also anticipate that we will add <privuser/> to force a
    private user ID namespace.
    
    * src/conf/domain_conf.c, src/conf/domain_conf.h: Add support
      for <privnet/> feature. Auto-set <privnet> if any <interface>
      devices are defined
    * src/lxc/lxc_container.c: Honour request for private network
      namespace

Because there is another bug 842979 make the lxc can't start normally , so i just add the xml to a shut down lxc and it works .
My question is that the steps is enough to verfiy the bug ? Or should we defer the bug until the lxc function works well.


1.
#rpm -q libvirt
libvirt-0.10.0-0rc1.el6.x86_64
#virsh -c lxc:///
virsh # list --all
 Id    Name                           State
----------------------------------------------------
 -     lxc                            shut off

2.
virsh # dumpxml lxc
<domain type='lxc'>
  <name>lxc</name>
  <uuid>2a0c59a1-519b-3865-582b-5339f5e1b95d</uuid>
  <memory unit='KiB'>1048576</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>
  <vcpu placement='static'>1</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>restart</on_crash>
  <devices>
    <emulator>/usr/libexec/libvirt_lxc</emulator>
    <interface type='network'>
      <mac address='00:16:3e:cb:17:2b'/>
      <source network='default'/>
    </interface>
    <console type='pty'>
      <target type='lxc' port='0'/>
    </console>
  </devices>
</domain>

3.
add the <privnet/> feature 
virsh#dumpxml lxc
<domain type='lxc'>
  <name>lxc</name>
  <uuid>2a0c59a1-519b-3865-582b-5339f5e1b95d</uuid>
  <memory unit='KiB'>1048576</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <os>
    <type arch='x86_64'>exe</type>
    <init>/bin/sh</init>
  </os>
  <features>
    <privnet/>                    <----success with no error
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/libexec/libvirt_lxc</emulator>
    <interface type='network'>
      <mac address='00:16:3e:cb:17:2b'/>
      <source network='default'/>
    </interface>
    <console type='pty'>
      <target type='lxc' port='0'/>
    </console>
  </devices>
</domain>

No, I think we should verify this on a running lxc domain.

(In reply to comment #7)
> No, I think we should verify this on a running lxc domain.

OK , i will verify this after the depends on's be fixed

verified bug with the steps in comment6 since the depends bugs is fixed.

Sorry for forgetting the pkg version
libvirt-0.10.2-2.el6.x86_64

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHSA-2013-0276.html