fake hypervisor plugin

Convert fake hypervisor configuration in Nova to the new plugin setup.

Change-Id: I8b1404ee97a2a65f0884efae642b98bb134cb2aa
Merge branch 'config-local' into dt-test
Merge branch 'hypervisor-xenserver' into dt-test
Merge branch 'hypervisor-powervm' into dt-test
Merge branch 'hypervisor-fake' into dt-test