Nova API os-hosts extension broken

Scenario: Update the status of a host using the os-hosts extension.

Branch: master
Request URL: http://127.0.0.1:8774/v2/03dce75fed734c019d87f30e738a0273/os-hosts/ubuntu-devstack
Request Body: {"status": "disable"}

Expected Result: The host status must be updated to 'disabled'.
Actual Result: API call fails with a 500 Internal Server Error.

Stack Trace:
    2012-03-20 05:15:01 ERROR nova.api.openstack [req-406770bf-4f57-4907-8ac4-1e8d52412321 f9e618906d8f479f800347a0f5db88f7 03dce75fed734c019d87f30e738a0273] Caught error:
    'HostAPI' object has no attribute '_call_compute_message'
    (nova.api.openstack): TRACE: Traceback (most recent call last):
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/__init__.py", line 41, in __call__
    (nova.api.openstack): TRACE: return req.get_response(self.application)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/request.py", line 1053, in get_response
    (nova.api.openstack): TRACE: application, catch_exc_info=False)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/request.py", line 1022, in call_application
    (nova.api.openstack): TRACE: app_iter = application(self.environ, start_response)
    (nova.api.openstack): TRACE: File "/opt/stack/keystone/keystone/middleware/auth_token.py", line 176, in __call__
    (nova.api.openstack): TRACE: return self.app(env, start_response)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 159, in __call__
    (nova.api.openstack): TRACE: return resp(environ, start_response)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 159, in __call__
    (nova.api.openstack): TRACE: return resp(environ, start_response)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 159, in __call__
    (nova.api.openstack): TRACE: return resp(environ, start_response)
    (nova.api.openstack): TRACE: File "/usr/lib/pymodules/python2.7/routes/middleware.py", line 131, in __call__
    (nova.api.openstack): TRACE: response = self.app(environ, start_response)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 159, in __call__
    (nova.api.openstack): TRACE: return resp(environ, start_response)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 147, in __call__
    (nova.api.openstack): TRACE: resp = self.call_func(req, *args, **self.kwargs)
    (nova.api.openstack): TRACE: File "/usr/lib/python2.7/dist-packages/webob/dec.py", line 208, in call_func
    (nova.api.openstack): TRACE: return self.func(req, *args, **kwargs)
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/wsgi.py", line 803, in __call__
    (nova.api.openstack): TRACE: content_type, body, accept)
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/wsgi.py", line 851, in _process_stack
    (nova.api.openstack): TRACE: action_result = self.dispatch(meth, request, action_args)
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/wsgi.py", line 926, in dispatch
    (nova.api.openstack): TRACE: return method(req=request, **action_args)
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/compute/contrib/hosts.py", line 114, in wrapped
    (nova.api.openstack): TRACE: return fn(self, req, id, *args, **kwargs)
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/compute/contrib/hosts.py", line 163, in update
    (nova.api.openstack): TRACE: result.update(update_setters[key](req, id, value))
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/api/openstack/compute/contrib/hosts.py", line 183, in _set_enabled_status
    (nova.api.openstack): TRACE: enabled=enabled)
    (nova.api.openstack): TRACE: File "/opt/stack/nova/nova/compute/api.py", line 1689, in set_host_enabled
    (nova.api.openstack): TRACE: return self._call_compute_message("set_host_enabled", context,
    (nova.api.openstack): TRACE: AttributeError: 'HostAPI' object has no attribute '_call_compute_message'
    (nova.api.openstack): TRACE: