remove unnecessary sleep after failed token renew
remove unnecessary sleep after failed token renew

When the vault token renewal process returns (due to failure or lease
ending) it had a unnecessary sleep in addition to the sleeps are part
of the renewal process. This sleep adds a slight delay before the normal
exponential backoff/retry semantics kick in and is useless (and
confusing).

hashicorp/consul-template,hashicorp/consul-template