ripd: fix compiler warnings

* ripd/rip_interface.c
  * rip_request_neighbor(): comment out, unused
  * rip_request_neighbor_all(): idem
  * rip_interface_up(): Cast flags otherwise compiler complains
    about %lld not matching uint64_t on 64 bit x86. Print in hex
    since flags are bit field.
  * rip_interface_add(): idem
  * rip_interface_delete(): idem
* ripd/rip_zebra.c
  * rip_redistribute_set(): comment out, unused
* ripd/ripd.h
  * rip_redistribute_check(): move prototype here so compiler
    can check function against prototype
* ripd/ripd.c
  * rip_update_default_metric(): comment out, unused
diff --git a/ripd/ripd.c b/ripd/ripd.c
index 2d5a856..5a6dbc8 100644
--- a/ripd/ripd.c
+++ b/ripd/ripd.c
@@ -2976,6 +2976,7 @@
   return CMD_SUCCESS;
 }
 
+#if 0
 static void
 rip_update_default_metric (void)
 {
@@ -2987,6 +2988,7 @@
       if (rinfo->type != ZEBRA_ROUTE_RIP && rinfo->type != ZEBRA_ROUTE_CONNECT)
         rinfo->metric = rip->default_metric;
 }
+#endif
 
 DEFUN (rip_default_metric,
        rip_default_metric_cmd,