flow: use rule priority in match_format() function

The flow_format() function was incorrectly passing skb_priority
to the match_format() function. match_format() function instead
expects rule priority.

This issue was introduced with aa6c9932f2
(Change logging format for flows to that accepted by ofproto/trace).

Signed-off-by: Ansis Atteka <aatteka@nicira.com>

lib/flow.c

@@ -529,7 +529,7 @@ flow_format(struct ds *ds, const struct flow *flow)
     struct match match;
 
     match_wc_init(&match, flow);
-    match_format(&match, ds, flow->skb_priority);
+    match_format(&match, ds, OFP_DEFAULT_PRIORITY);
 }
 
 void