Improve documentation for the last fix of bug 932.

src/or/geoip.c

@@ -389,7 +389,10 @@ _remove_old_client_helper(struct clientmap_entry_t *ent, void *_cutoff)
   }
 }
 
-/** Forget about all clients that haven't connected since <b>cutoff</b>. */
+/** Forget about all clients that haven't connected since <b>cutoff</b>.
+ * If <b>cutoff</b> is in the future, clients won't be added to the history
+ * until this time is reached. This is useful to prevent relays that switch
+ * to bridges from reporting unbelievable numbers of clients. */
 void
 geoip_remove_old_clients(time_t cutoff)
 {