lib: address -Wunused-but-set-variable

* if.c
  * if_dump(): 'node', 'c'
* distribute.c
  * distribute_list_all(): 'dist'
  * distribute_list(): 'dist'
  * districute_list_prefix_all(): 'dist'
* if_rmap.c
  * if_rmap(): 'if_rmap'
* vty.c
  * vty_accept(): 'vty'
diff --git a/lib/if_rmap.c b/lib/if_rmap.c
index ddc62fd..b49d266 100644
--- a/lib/if_rmap.c
+++ b/lib/if_rmap.c
@@ -212,7 +212,6 @@
        "Route map interface name\n")
 {
   enum if_rmap_type type;
-  struct if_rmap *if_rmap;
 
   if (strncmp (argv[1], "i", 1) == 0)
     type = IF_RMAP_IN;
@@ -224,7 +223,7 @@
       return CMD_WARNING;
     }
 
-  if_rmap = if_rmap_set (argv[2], type, argv[0]);
+  if_rmap_set (argv[2], type, argv[0]);
 
   return CMD_SUCCESS;
 }