I'm trying to run an AWS_PROXY integration between APIGateway and Lambda, and I'm hitting what looks like a fundamental logic bug in the APIGateway implementation.

https://github.com/localstack/localstack/blob/master/localstack/services/apigateway/apigateway_listener.py#L101

```
 File "/opt/code/localstack/localstack/services/apigateway/apigateway_listener.py", line 101, in forward_request
    'resourceId': resource.get('id'),
UnboundLocalError: local variable 'resource' referenced before assignment
```

Scanning up the file, it looks like `resource` is only be initialized within a `catch` block.  I assume this is a simple oversight rather than a complex bug.

This looks like a bug I can fix, but I'd appreciate any guidance you can offer.
response.headers.update(parsed_result.get('headers', {}))
                    try:
                        if isinstance(parsed_result['body'], dict):
                            response._content = json.dumps(parsed_result['body'])
                        else:
                            response._content = parsed_result['body']
                    except Exception:
                        response._content = '{}'
                    return response
                else:
                    msg = 'API Gateway action uri "%s" not yet implemented' % uri
                    LOGGER.warning(msg)
                    return make_error(msg, 404)
            elif integration['type'] == 'HTTP':
                function = getattr(requests, method.lower())
                if isinstance(data, dict):
                    data = json.dumps(data)
                result = function(integration['uri'], data=data, headers=headers)
                return result
            else:
                msg = ('API Gateway integration type "%s" for method "%s" not yet implemented' %
                       (integration['type'], method))
                LOGGER.warning(msg)
                return make_error(msg, 404)
            return 200
        if re.match(PATH_REGEX_AUTHORIZERS, path):
            return handle_authorizers(method, path, data, headers)
        return True
UPDATE_APIGATEWAY = ProxyListenerApiGateway()