Reconnect and retry if image backup block number is corrupted
Reconnect and retry if image backup block number is corrupted

(cherry picked from commit da61f8b001bef6ef60d2276cf9e8d37eb4eca810)

uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend