## 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"
        }
    ]
}
```
stream = data['StreamSpecification']
    enabled = stream.get('StreamEnabled')
    if enabled not in [False, 'False']:
        table_name = data['TableName']
        view_type = stream['StreamViewType']
        dynamodbstreams_api.add_dynamodb_stream(table_name=table_name,
            latest_stream_label=latest_stream_label, view_type=view_type, enabled=enabled)
def forward_to_lambda(records):
    for record in records:
        sources = lambda_api.get_event_sources(source_arn=record['eventSourceARN'])
        event = {
            'Records': [record]
        }
        for src in sources:
            lambda_api.run_lambda(event=event, context={}, func_arn=src['FunctionArn'])
def forward_to_ddb_stream(records):
    dynamodbstreams_api.forward_events(records)
def dynamodb_extract_keys(item, table_name):
    result = {}
    if table_name not in TABLE_DEFINITIONS:
        LOGGER.warning('Unknown table: %s not found in %s' % (table_name, TABLE_DEFINITIONS))
        return None
    for key in TABLE_DEFINITIONS[table_name]['KeySchema']:
        attr_name = key['AttributeName']
        if attr_name not in item:
            return error_response(error_type='ValidationException',
                message='One of the required keys was not given a value')
        result[attr_name] = item[attr_name]
    return result
def error_response(message=None, error_type=None, code=400):