With today's update, API Gateway consistently fails to find any of its' defined paths.

For example, the following `serverless.yml` :
```yaml
service: "localtest"

provider:
  name: "aws"
  runtime: "nodejs10.x"

functions:
  hello:
    handler: "handler.hello"
    events:
      - http:
          path: "/"
          method: "get"
          integration: "lambda-proxy"
      - http:
          path: "/test"
          method: "get"
          integration: "lambda-proxy"
plugins:
  - "serverless-localstack"

custom:
  localstack:
    stages:
      - "local"
```

If deployed, will result in the following:
```
~$ sls deploy --stage local
Serverless: Using serverless-localstack
Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
.
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service localtest.zip file to S3 (3.02 KB)...
Serverless: Validating template...
Serverless: Skipping template validation: Unsupported in Localstack
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
.
Serverless: Stack update finished...
Service Information
service: localtest
stage: local
region: us-east-1
stack: localtest-local
resources: 11
api keys:
  None
endpoints:
  GET - http://localhost:4567/restapis/sz3ijrff91/local/_user_request_/
  GET - http://localhost:4567/restapis/sz3ijrff91/local/_user_request_/test
functions:
  hello: localtest-local-hello
layers:
  None
Serverless: Run the "serverless" command to setup monitoring, troubleshooting and testing.
~$ curl http://localhost:4567/restapis/sz3ijrff91/local/_user_request_/
{"message": "Unable to find integration for path /restapis/sz3ijrff91/local/_user_request_/"}
~$ curl http://localhost:4567/restapis/sz3ijrff91/local/_user_request_/test
{"message": "Unable to find integration for path /restapis/sz3ijrff91/local/_user_request_/test"}
```
parsed_result = common.json_safe(parsed_result)
            response.status_code = int(parsed_result.get('statusCode', 200))
            response.headers.update(parsed_result.get('headers', {}))
            try:
                if isinstance(parsed_result['body'], dict):
                    response._content = json.dumps(parsed_result['body'])
                else:
                    response._content = to_bytes(parsed_result['body'])
            except Exception:
                response._content = '{}'
            response.headers['Content-Length'] = len(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
UPDATE_APIGATEWAY = ProxyListenerApiGateway()