## Issue description
When creating a CloudFormation stack, the `CreationDate` is always `2011-05-23T15:47:44Z`

## Steps to reproduce
1. Prepare a CloudFormation file, for example
```yml
AWSTemplateFormatVersion: 2010-09-09
Description: My Stack
Resources:
  LambdaCodeBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: my-bucket
```
2. Create a new stack based on this file, I used the command:
```bash
awslocal cloudformation create-stack --stack-name gch --template-body file://stack.yml
```
3. List all the created stacks and confirm the `CreationDate` is not a present date
```
awslocal cloudformation list-stacks
```
```
{
    "StackSummaries": [
        {
            "StackId": "arn:aws:cloudformation:us-east-1:000000000000:stack/stack/27187f13-a645-40a0-8788-62d502358216",
            "StackName": "stack",
            "TemplateDescription": "My Stack",
            "CreationTime": "2011-05-23T15:47:44Z",
            "StackStatus": "CREATE_COMPLETE"
        }
    ]
}
```
status_code = 0 if response is None else response.status_code
        if not response or status_code == 301 or status_code >= 400:
            
            if '://localhost' in url or re.match(r'.*s3(\-website)?\.([^\.]+\.)?amazonaws.com.*', url):
                parsed_path = urlparse.urlparse(url).path.lstrip('/')
                parts = parsed_path.partition('/')
                client = aws_stack.connect_to_service('s3')
                result = client.get_object(Bucket=parts[0], Key=parts[2])
                body = to_str(result['Body'].read())
                return body
            raise Exception('Unable to fetch template body (code %s) from URL %s' % (status_code, url))
        return response.content
    raise Exception('Unable to get template body from input: %s' % req_data)
class ProxyListenerCloudFormation(ProxyListener):
    def forward_request(self, method, path, data, headers):
        if method == 'OPTIONS':
            return 200
        req_data = None
        if method == 'POST' and path == '/':
            req_data = urlparse.parse_qs(to_str(data))
            req_data = dict([(k, v[0]) for k, v in req_data.items()])
            action = req_data.get('Action')
            stack_name = req_data.get('StackName')
            if action == 'CreateStack':
                event_publisher.fire_event(event_publisher.EVENT_CLOUDFORMATION_CREATE_STACK,
                    payload={'n': event_publisher.get_hash(stack_name)})
            if action == 'DeleteStack':
                client = aws_stack.connect_to_service('cloudformation')
                stack_resources = client.list_stack_resources(StackName=stack_name)['StackResourceSummaries']
                template_deployer.delete_stack(stack_name, stack_resources)