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. 
bucket_name = normalize_bucket_name(bucket_name)
    
    if isinstance(to_str(encryption), six.string_types):
        encryption = xmltodict.parse(encryption)
    BUCKET_ENCRYPTIONS[bucket_name] = encryption
    return 200
def set_object_lock(bucket_name, lock_config):
    bucket_name = normalize_bucket_name(bucket_name)
    
    if isinstance(to_str(lock_config), six.string_types):
        lock_config = xmltodict.parse(lock_config)
    OBJECT_LOCK_CONFIGS[bucket_name] = lock_config
    return 200
def strip_chunk_signatures(data):
    
    
    #
    
    
    
    data_new = re.sub(b'(^|\r\n)[0-9a-fA-F]+;chunk-signature=[0-9a-f]{64}(\r\n)(\r\n$)?', b'',
        data, flags=re.MULTILINE | re.DOTALL)
    return data_new
def bucket_exists(bucket_name):