Fix a stupid logic-error in warnings about low ports.

Instead of warning about low ports that are advertised, we should have
been warning about low ports that we're listening on.  Bug 7285, fix
on 0.2.3.9-alpha.

changes/bug7285

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - Warn when we are binding low ports when hibernation is enabled;
+      previously we had warned when we were _advertising_ low ports with
+      hibernation enabled. Fixes bug 7285; bugfix on 0.2.3.9-alpha.

src/or/config.c

@@ -5004,7 +5004,7 @@ check_server_ports(const smartlist_t *ports,
       continue;
     }
 #ifndef _WIN32
-    if (!port->no_advertise && port->port < 1024)
+    if (!port->no_listen && port->port < 1024)
       ++n_low_port;
 #endif
   } SMARTLIST_FOREACH_END(port);