Print the correct address family in log printout.

Look at the address family of the preferred OR port rather than the
node.ipv6_preferred flag since the logic has changed with new
ClientUseIPv6 config option.

Fixes ticket 6884.

changes/6884

@@ -0,0 +1,4 @@
+  o Minor bugfixes (client):
+    - Correct log printout about which address family is preferred
+      when connecting to a bridge with both an IPv4 and IPv6 OR port.
+      Fixes bug 6884.

src/or/circuitbuild.c

@@ -5641,7 +5641,7 @@ rewrite_node_address_for_bridge(const bridge_info_t *bridge, node_t *node)
                  "Bridge '%s' has both an IPv4 and an IPv6 address.  "
                  "Will prefer using its %s address (%s:%d).",
                  ri->nickname,
-                 node->ipv6_preferred ? "IPv6" : "IPv4",
+                 tor_addr_family(&ap.addr) == AF_INET6 ? "IPv6" : "IPv4",
                  fmt_addr(&ap.addr), ap.port);
     }
   }