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.
import re
import logging
import json
import requests
from requests.models import Response
from flask import Response as FlaskResponse
from localstack.constants import APPLICATION_JSON, PATH_USER_REQUEST
from localstack.config import TEST_KINESIS_URL
from localstack.utils import common
from localstack.utils.aws import aws_stack
from localstack.utils.common import to_str
from localstack.services.awslambda import lambda_api