## 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"
        }
    ]
}
```
elif action == '%s.TagResource' % ACTION_PREFIX or action == '%s.UntagResource' % ACTION_PREFIX:
            response = Response()
            response.status_code = 200
            response._content = ''  
            fix_headers_for_updated_response(response)
            return response
        elif action == '%s.ListTagsOfResource' % ACTION_PREFIX:
            response = Response()
            response.status_code = 200
            response._content = json.dumps({'Tags': []})  
            fix_headers_for_updated_response(response)
            return response
        return True
    def return_response(self, method, path, data, headers, response):
        if path.startswith('/shell') or method == 'GET':
            return
        data = json.loads(to_str(data))
        
        if data and 'TableName' in data and 'KeySchema' in data:
            TABLE_DEFINITIONS[data['TableName']] = data
        if response._content:
            
            content_replaced = re.sub(r'("TableArn"|"LatestStreamArn"|"StreamArn")\s*:\s*"arn:aws:dynamodb:' +
            'ddblocal:([^"]+)"', r'\1: "arn:aws:dynamodb:%s:\2"' % aws_stack.get_region(),
            to_str(response._content))
            if content_replaced != response._content:
                response._content = content_replaced
                fix_headers_for_updated_response(response)
        action = headers.get('X-Amz-Target')
        if not action: