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. 
""" Class to handle putting with urllib """
    def __init__(self, *args, **kwargs):
        return Request.__init__(self, *args, **kwargs)
    def get_method(self, *args, **kwargs):
        return 'PUT'
class S3ListenerTest(unittest.TestCase):
    def setUp(self):
        self.s3_client = aws_stack.connect_to_service('s3')
        self.sqs_client = aws_stack.connect_to_service('sqs')
    def test_create_bucket_via_host_name(self):
        body = """<?xml version="1.0" encoding="UTF-8"?>
            <CreateBucketConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
                <LocationConstraint>eu-central-1</LocationConstraint>
            </CreateBucketConfiguration>"""
        headers = aws_stack.mock_aws_request_headers('s3')
        bucket_name = 'test-%s' % short_uid()
        headers['Host'] = '%s.s3.amazonaws.com' % bucket_name
        response = requests.put(config.TEST_S3_URL, data=body, headers=headers, verify=False)
        self.assertEquals(response.status_code, 200)
        response = self.s3_client.get_bucket_location(Bucket=bucket_name)
        self.assertEqual(response['ResponseMetadata']['HTTPStatusCode'], 200)
        self.assertIn('LocationConstraint', response)
    def test_bucket_policy(self):