We are seeing that replication tasks occasionally sit around forever and
have had to take manual intervention. One theory is that this is related
to networking between the gerrit server and the gitea servers. We don't
set maxRetries which means replication should be retried infinitely
which means if we hit the timeout we should try again. 15 minutes was
sort of arbitrarily chosen as ~twice the time it takes to clone a large
repo like nova.
Change-Id: Iec2536ad149a2e625a1f0107b9fcee3079493607
f1bcb6a586