Proper hash send error failure handling
Proper hash send error failure handling

(cherry picked from commit 9424989a6a657b1330f356488558638a8c3db57b)

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