Description of problem:
With latest snap #8 libvirt doesn't create bridged network on the host system. I have my ifcfg files correctly setup (as per documentation) and virt-manager shows only NAT network. 

/var/log/messages says:

Jul 27 07:50:52 hp-bl685cg6-01 libvirtd: 07:50:52.906: error : interfaceNumOfInterfaces:187 : internal error failed to get number of interfaces on host (netcf: unspecified error - errors in loading some config files)
Jul 27 07:50:52 hp-bl685cg6-01 libvirtd: 07:50:52.920: error : interfaceNumOfDefinedInterfaces:229 : internal error failed to get number of defined interfaces on host (netcf: unspecified error - errors in loading some config files)

Which keeps repeating. 

Version-Release number of selected component (if applicable):
libvirt-0.8.1-15.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. Install and start libvirt
2. Configure bridged networking as per Virtualization Guide document
3.
  
Actual results:
ifconfig reports successfull creation of the br0 bridge device but libvirt fails to detect/use this. There are errors in /var/log/messages and virt-manager.log.

Expected results:
libvirt uses the bridged device for default networking of virtual guests.

Additional info:

The virt-manager log error is:

[Tue, 27 Jul 2010 07:54:52 virt-manager 2471] ERROR (connection:1245) Unable to list inactive interfaces
Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/connection.py", line 1243, in _update_interfaces
    newInactiveNames = self.vmm.listDefinedInterfaces()
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 1789, in listDefinedInterfaces
    if ret is None: raise libvirtError ('virConnectListDefinedInterfaces() failed', conn=self)
libvirtError: internal error failed to get number of defined interfaces on host (netcf: unspecified error - errors in loading some config files)


My ifcfg files are:
ifcfg-eth0 

DEVICE="eth0"
HWADDR="00:24:81:AB:E0:08"
ONBOOT="yes"
BRIDGE=br0


ifcfg-br0 

DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
DELAY=0


NetworkManager is off, network is on.