fix set never used warnings

(This patch was modified to leave calls to stream_getl() in place, they
are necessary for the stream's internal pointer to advance to the
correct position. -- Denis)

Signed-off-by: Denis Ovsienko <infrastation@yandex.ru>

Fix gcc warnings about varables that are set but never used.

* bgpd/bgp_attr.c
  * cluster_unintern(): ret
  * transit_unintern(): ret
  * bgp_attr_default_intern(): attre
  * bgp_mp_reach_parse(): rd_high, rd_low
* bgpd/bgp_route.c
  * bgp_announce_check_rsclient(): bgp
* bgpd/bgp_zebra.c
  * zebra_read_ipv4(): ifindex
  * zebra_read_ipv6(): ifindex
* bgpd/bgpd.c
  * bgp_config_write_peer(): filter
* lib/distribute.c
  * distribute_list_all(): dist
  * distribute_list(): dist
  * distribute_list_prefix_all(): dist
  * distribute_list_prefix(): dist
* lib/if_rmap.c
  * if_rmap(): if_rmap
* lib/vty.c
  * vty_accept(): vty
* lib/zclient.c
  * zclient_read(): ret
* zebra/irdp_interface.c
  * if_group(): zi
* zebra/rt_netlink.c
  * kernel_read(): ret, sock
diff --git a/lib/if_rmap.c b/lib/if_rmap.c
index 9774be4..7d049b8 100644
--- a/lib/if_rmap.c
+++ b/lib/if_rmap.c
@@ -207,7 +207,6 @@
        "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;
@@ -219,7 +218,7 @@
       return CMD_WARNING;
     }
 
-  if_rmap = if_rmap_set (argv[2], type, argv[0]);
+  if_rmap_set (argv[2], type, argv[0]);
 
   return CMD_SUCCESS;
 }