Description of problem:
The value of default pinning should be shown correctly according to the Runtime pinning values when the guest is running.

Version-Release number of selected component (if applicable):
libvirt-0.9.4-1.el6.x86_64
virt-manager-0.9.0-5.el6.x86_64
qemu-kvm-0.12.1.2-2.175.el6.x86_64
python-virtinst-0.600.0-2.el6.noarch
kernel-2.6.32-171.el6.x86_64


How reproducible:
always

Steps to Reproduce:
1.Shut down a guest. set the value of "Default pinning" is "NULL"(empty),apply.

2.Boot up the guest. 
  The value of default pinning is shown as "NULL"(empty), while Runtime pinning has values. and i think the value of default pinning should be shown as "0-3" according to the Runtime pinning.

3.set the value of "Default pinning" is "0-2",apply. 
  The value of default pinning is shown as "NULL"(empty), and i think it should be shown as "0-2";

4.Shut down a guest. set the value of "Default pinning" is "1-3",apply.

5.Boot up the guest. set the value of "Default pinning" is "0-2",apply. 
  The value of default pinning is shown as "1-3", and i think it should be shown as "0-2";
  
Actual results:
see "Steps to Reproduce"

Expected results:
see "Steps to Reproduce"

Additional info: