[MTurk] bug where first message sometimes dropped from use_db save (#1523)
[MTurk] bug where first message sometimes dropped from use_db save (#1523)

* [MTurk] fix bug where first message would rarely be dropped from saving with use_db"

* lint fix

facebookresearch/ParlAI,facebookresearch/ParlAI,facebookresearch/ParlAI,facebookresearch/ParlAI,facebookresearch/ParlAI