hs: Don't retry to open a service RP circuit while iterating on the circuit list
Turns out that hs_circ_retry_service_rendezvous_point()
is being called in the circuit loop of circuit_expire_building()
and this is no good at all because it means we are adding an item to the circuit global list while iterating on it.
Instead, we should call it when hs_service_circuit_cleanup_on_close()
is called, if the closing circuit was in CIRCUIT_PURPOSE_S_CONNECT_REND
state, retry.