Description of problem:
libvirtd crash when edit a net with some operation

Version-Release number of selected component (if applicable):
libvirt-0.10.2-2.el6.x86_64
qemu-kvm-0.12.1.2-2.316.el6.x86_64
kernel-2.6.32-312.el6.x86_64

How reproducible:
100%
1 # virsh net-list --all
Name                 State      Autostart     Persistent
--------------------------------------------------
default              inactive   yes           yes
 virsh net-edit default
<network>
  <name>default</name>
  <uuid>a9b504eb-0c98-4736-bbda-97b2cd9f9d0e</uuid>
  <forward mode='nat'/>
  <bridge name='virbr0' stp='on' delay='0' />
  <mac address='00:00:00:00:00:00'/>
  <ip address='192.168.122.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254' />
    </dhcp>
  </ip>
</network>
# virsh net-start default
error: Failed to start network default
error: Cannot set interface MAC on 'virbr0-nic': Cannot assign requested address

3 modified the mac to the correct one,then do some operation about the default net
#virsh net-edit default
<network>
  <name>default</name>
  <uuid>a9b504eb-0c98-4736-bbda-97b2cd9f9d0e</uuid>
  <forward mode='nat'/>
  <bridge name='virbr0' stp='on' delay='0' />
  <mac address='00:00:00:00:00:01'/>
  <ip address='192.168.122.1' netmask='255.255.255.0'>
    <dhcp>
      <range start='192.168.122.2' end='192.168.122.254' />
    </dhcp>
  </ip>
</network>
# virsh net-start default
Network default started

# virsh net-list
Name                 State      Autostart     Persistent
--------------------------------------------------
default              active     yes           yes

# virsh net-destroy default
Network default destroyed

# virsh net-edit default
error: failed to get network 'default'
error: End of file while reading data: Input/output error
error: Failed to reconnect to the hypervisor

 
Actual results:
the libvirtd crashed,while edit the net

Expected results:
The net should be edit successfully,and the libvirtd should keep running

Additional info