event-list fails for Autoscaling example template

As observed/reported by ppetit, there is a problem with the event-list API action for stacks using Autoscaling groups.

Steps to reproduce:

heat-cfn create autoscale2 --template-file=templates/AutoScalingMultiAZSample.template --parameters="InstanceType=m1.xlarge;DBUsername=${USER};DBPassword=verybadpass;KeyName=${USER}_key"

<wait for stack to create>

 heat-cfn event-list autoscale2
ERROR:Failed to event-list. Got error:
ERROR:Internal Server error: <ErrorResponse><Error><Message>The request processing has failed due to an internal error:u'WebServerGroup-0'</Message><Code>InternalFailure</Code><Type>Server</Type></Error></ErrorResponse>

engine log, looks like a resource name lookup issue (something needs physical_resource_name()?)

2012-12-12 11:33:02 ERROR [heat.openstack.common.rpc.amqp] Exception during message handling
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/heat-2013.1-py2.7.egg/heat/openstack/common/rpc/amqp.py", line 276, in _process_data
    rval = self.proxy.dispatch(ctxt, version, method, **args)
  File "/usr/lib/python2.7/site-packages/heat-2013.1-py2.7.egg/heat/openstack/common/rpc/dispatcher.py", line 147, in dispatch
    return getattr(proxyobj, method)(ctxt, **kwargs)
  File "/usr/lib/python2.7/site-packages/heat-2013.1-py2.7.egg/heat/engine/service.py", line 44, in wrapped
    return func(self, ctx, *args, **kwargs)
  File "/usr/lib/python2.7/site-packages/heat-2013.1-py2.7.egg/heat/engine/service.py", line 344, in list_events
    output = [api.format_event(Event.load(context, e.id)) for e in events]
  File "/usr/lib/python2.7/site-packages/heat-2013.1-py2.7.egg/heat/engine/event.py", line 57, in load
    resource = stack[ev.logical_resource_id]
  File "/usr/lib/python2.7/site-packages/heat-2013.1-py2.7.egg/heat/engine/parser.py", line 166, in __getitem__
    return self.resources[key]
KeyError: u'WebServerGroup-0'