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.
except Exception:
                        return make_error('Unable to find path %s' % path, 404)
                    integrations = resource.get('resourceMethods', {})
                    integration = integrations.get(method, {})
                    if not integration:
                        integration = integrations.get('ANY', {})
                    integration = integration.get('methodIntegration')
                    if not integration:
                        if method == 'OPTIONS' and 'Origin' in headers:
                            
                            return get_cors_response(headers)
                        return make_error('Unable to find integration for path %s' % path, 404)
            uri = integration.get('uri')
            if method == 'POST' and integration['type'] == 'AWS':
                if uri.endswith('kinesis:action/PutRecords'):
                    template = integration['requestTemplates'][APPLICATION_JSON]
                    new_request = aws_stack.render_velocity_template(template, data)
                    
                    headers = aws_stack.mock_aws_request_headers(service='kinesis')
                    headers['X-Amz-Target'] = kinesis_listener.ACTION_PUT_RECORDS
                    result = common.make_http_request(url=TEST_KINESIS_URL,
                        method='POST', data=new_request, headers=headers)
                    return result
                else:
                    msg = 'API Gateway action uri "%s" not yet implemented' % uri
                    LOGGER.warning(msg)
                    return make_error(msg, 404)
            elif integration['type'] == 'AWS_PROXY':
                if uri.startswith('arn:aws:apigateway:') and ':lambda:path' in uri:
                    func_arn = uri.split(':lambda:path')[1].split('functions/')[1].split('/invocations')[0]