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 json
import unittest
from requests.models import Response
from localstack.constants import DEFAULT_REGION, TEST_AWS_ACCOUNT_ID
from localstack.config import INBOUND_GATEWAY_URL_PATTERN
from localstack.utils import testutil
from localstack.utils.aws import aws_stack
from localstack.utils.common import to_str, load_file
from localstack.utils.common import safe_requests as requests
from localstack.services.generic_proxy import GenericProxy, ProxyListener
from localstack.services.awslambda.lambda_api import (LAMBDA_RUNTIME_PYTHON27)
from localstack.services.apigateway.helpers import get_rest_api_paths, get_resource_for_path
from .test_lambda import TEST_LAMBDA_PYTHON, TEST_LAMBDA_LIBS
class TestAPIGatewayIntegrations(unittest.TestCase):