Description of problem:
When you rename a fencing device that is referenced within an instance with Unfence enabled, the Unfence reference does not get updated with the new name and will refer to a non-existent device.



Version-Release number of selected component (if applicable):
luci-0.26.0-29.el6.i686


How reproducible:
Always


Steps to Reproduce:

1. Create a new fencing device

2. On a selected cluster node, define a new fencing method + instance with Unfence enabled
The cluster.conf snippet will look like this: 
<clusternode name="z2" nodeid="1">
  <unfence>
    <device action="enable" name="myfence" port="1"/>
  </unfence>
  <fence>
    <method name="Method">
      <device name="myfence" port="1"/>
    </method>
  </fence>
</clusternode>
<fencedevices>
  <fencedevice agent="fence_brocade" ipaddr="ipaddr" login="root" name="myfence" passwd="password"/>
</fencedevices>

3. Rename the "myfence" device to "newfence". Cluster.conf snippet will look like this (notice the invalid reference in unfence section):
<clusternode name="z2" nodeid="1">
  <unfence>
    <device action="enable" name="myfence" port="1"/>
  </unfence>
  <fence>
    <method name="Method">
      <device name="newfence" port="1"/>
    </method>
  </fence>
</clusternode>
<fencedevices>
  <fencedevice agent="fence_brocade" ipaddr="ipaddr" login="root" name="newfence" passwd="password"/>
</fencedevices>



Actual results:
Unfence reference is not updated.


Expected results:
Unfence reference is updated.