Hello all,

I have noticed that when I generate a presigned url for a file that will be uploaded to S3 that the Lambda function does not get triggered. It seems to only be happening for presigned url. I was able to successful have it trigger when I use the command line and upload a file through `aws s3 cp`. 

To recreate:
1: have any lambda function be added to an s3 bucket. My lambda configurations look as followed:
```
aws s3api --endpoint-url=http://localstack:4572 create-bucket --bucket mybucket;
aws s3api --endpoint-url=http://localstack:4572 create-bucket --bucket code;
aws s3 cp --endpoint-url=http://localstack:4572 --acl public-read /resources/example.zip s3://code/;
aws lambda create-function --endpoint-url=http://localstack:4574 --function-name MyLambdaFunction--runtime 'nodejs8.10' --handler 'index.handler' --role 'anyRole' --code S3Bucket=code,S3Key=example.zip,S3ObjectVersion=1.0.0;
```
Then add this lambda configuration to the bucket
```
{
    "LambdaFunctionConfigurations": [
        {
            "LambdaFunctionArn": "arn:aws:lambda:us-east-1:000000000000:function:MyLambdaFunction",
            "Events": [
                "s3:ObjectCreated:*"
            ]
        }
    ]
}
```
by running
```
aws s3api --endpoint-url=http://localstack:4572 put-bucket-notification-configuration --bucket 'mybucket' --notification-configuration file:///resources/notification.json;
```
2: Generate a presigned url for the bucket you added the lambda too

```
aws s3 presign --endpoint-url=http://localstack:4572 s3://mybucket/test.txt  --expires-in 300
```
3:
```
 curl --upload-file test.txt -v http://localstack:4572/mybucket/test.txt?AWSAccess
KeyId=dummyaccess&Expires=1571680684&Signature=TbCFh1rzkNYwNEooaQKcJPF4%2Fss%3D
```

Lambda does not seem to get triggered.

Any help or fixes?

Thank you so much for your time and help. Localstack has been a great tool!
"""Add Last-Modified header with current time
    (if the response content is an XML containing <LastModified>, add that instead)"""
    time_format = '%a, %d %b %Y %H:%M:%S GMT'  
    try:
        if content:
            last_modified_str = re.findall(r'<LastModified>(.*)</LastModified>', content)
            if last_modified_str:
                last_modified_str = last_modified_str[0]
                last_modified_time_format = dateutil.parser.parse(last_modified_str).strftime(time_format)
                response.headers['Last-Modified'] = last_modified_time_format
    except TypeError as err:
        LOGGER.debug('No parsable content: %s' % err)
    except ValueError as err:
        LOGGER.error('Failed to parse LastModified: %s' % err)
    except Exception as err:
        LOGGER.error('Caught generic exception (parsing LastModified): %s' % err)
    
    try:
        if response.headers.get('Last-Modified', '') == '':
            response.headers['Last-Modified'] = datetime.datetime.now().strftime(time_format)
    except Exception as err:
        LOGGER.error('Caught generic exception (setting LastModified header): %s' % err)
def get_lifecycle(bucket_name):