Comment 0 for bug 1730335

In order to avoid the expiration of the message is deleted, when the message is still claim status.
In this case, zaqar will modifies the message ttl. But the ttl gets smaller (currently this ttl=claim_ttl+claim_grace)
and may be less than age. I think this is a problem, and it should use ttl=ttl+claim_ttl+claim_grace.