Hi!

I have noticed that today (25th of Feb) a new version of localstack docker image was pushed to the repository (82c83ff027114060938856eac5dc7be1d534afd0b7711510246de4a76dde2396) and this version fails in my integration tests with an exception:

```
2020-02-25T12:09:44:ERROR:localstack.services.generic_proxy: Error forwarding request: An error occurred (404) when calling the HeadObject operation: Not Found Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/generic_proxy.py", line 303, in forward updated_response = self.proxy.update_listener.return_response(**kwargs)
  File "/opt/code/localstack/localstack/services/s3/s3_listener.py", line 954, in return_response
send_notifications(method, bucket_name, object_path, version_id)
  File "/opt/code/localstack/localstack/services/s3/s3_listener.py", line 178, in send_notifications
send_notification_for_subscriber(notif, bucket_name, object_path,
  File "/opt/code/localstack/localstack/services/s3/s3_listener.py", line 191, in send_notification_for_subscriber
object_size = s3_client.head_object(Bucket=bucket_name, Key=key).get('ContentLength', 0)
  File "/opt/code/localstack/.venv/lib/python3.8/site-packages/botocore/client.py", line 316, in _api_call
return self._make_api_call(operation_name, kwargs)
  File "/opt/code/localstack/.venv/lib/python3.8/site-packages/botocore/client.py", line 626, in _make_api_call
  raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (404) when calling the HeadObject operation: Not Found
```
The same setup in docker-compose works with version 0.10.7 and 0.10.6 without any errors or exceptions. 
key_by_path = 'key-by-hostname'
        key_by_host = 'key-by-host'
        queue_url, queue_attributes = self._create_test_queue()
        self._create_test_notification_bucket(queue_attributes)
        self.s3_client.put_bucket_versioning(Bucket=TEST_BUCKET_WITH_NOTIFICATION,
                                             VersioningConfiguration={'Status': 'Enabled'})
        
        obj = self.s3_client.put_object(Bucket=TEST_BUCKET_WITH_NOTIFICATION, Key=key_by_path, Body='something')
        
        
        headers = {'Host': '{}.s3.amazonaws.com'.format(TEST_BUCKET_WITH_NOTIFICATION), 'authorization': 'some_token'}
        url = '{}/{}'.format(config.TEST_S3_URL, key_by_host)
        
        response = requests.put(url, data='something else', headers=headers, verify=False)
        self.assertTrue(response.ok)
        self.assertEqual(self._get_test_queue_message_count(queue_url), '2')
        response = self.sqs_client.receive_message(QueueUrl=queue_url)
        messages = [json.loads(to_str(m['Body'])) for m in response['Messages']]
        record = messages[0]['Records'][0]
        self.assertIsNotNone(record['s3']['object']['versionId'])
        self.assertEquals(record['s3']['object']['versionId'], obj['VersionId'])
        
        self.s3_client.put_bucket_versioning(Bucket=TEST_BUCKET_WITH_NOTIFICATION,
                                             VersioningConfiguration={'Status': 'Disabled'})
        self.sqs_client.delete_queue(QueueUrl=queue_url)
        self._delete_bucket(TEST_BUCKET_WITH_NOTIFICATION, [key_by_path, key_by_host])
    def generate_large_file(self, size):