Clearer message regardings alternate bulk operations.

Fixes elastic#107, thanks jwarzech!

Author: honzakral

elasticsearch/helpers/__init__.py

@@ -58,8 +58,8 @@ def streaming_bulk(client, actions, chunk_size=500, raise_on_error=False, expand
  Alternatively, if `_source` is not present, it will pop all metadata fields
  from the doc and use the rest as the document data.
 
- Alternative actions (`_op_type` field defaults to `index`) can be sent as
- well::
+ If you wish to perform other operations, like `delete` or `update` use the
+ `_op_type` field in your actions (`_op_type` defaults to `index`)::
 
  {
  '_op_type': 'delete',