Renewer could miss write a document in carry-over db

[martin-d-aleksandrov]

In case a document is renewed and carry-over db is down, renewer will retry renew the same document, which would result in 409 response from Abacus. This would lead to bypass carry-over write.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/153281970

The labels on this github issue will be updated when the story is started.