BulkSaveError throws empty message.

Using bulk save, with a list containing the same document twice, BulkSaveError is properly thrown, but error is empty.

try:
db.bulk_save([docA, docB, docB])
except BulkSaveError, e:
# e is empty

CouchDB will return 201. First instance of docB is good in the response, second instance will contain:
{'reason': 'Document update conflict.', 'id': 'docid', 'error': 'conflict'}

Start at the db.bulk_save entry point and the BulkSaveError handling described in the issue. Reproduce the duplicate-document case with docB listed twice, inspect the CouchDB response containing the conflict reason, and verify that the raised error exposes that response rather than an empty message.

Written by the indexing model from the issue text.