Low: fencing: Set 'on_target=true' for fence_dummy to allow testing unfencing
Fix: fencing: properly detect new fencing devices for v2 cib updates

When a new resource is added, the xpath of the change is
/cib/configuration/resources/ not /cib/configuration/resources/primitive
Stonith was passing over new fencing devices added after the cluster
was initialized.
Merge pull request #493 from davidvossel/unfencing_fixes

Unfencing fixes