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/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 4e604b1..a2d4f4b 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -175,14 +175,12 @@
 void
 cluster_unintern (struct cluster_list *cluster)
 {
-  struct cluster_list *ret;
-
   if (cluster->refcnt)
     cluster->refcnt--;
 
   if (cluster->refcnt == 0)
     {
-      ret = hash_release (cluster_hash, cluster);
+      hash_release (cluster_hash, cluster);
       cluster_free (cluster);
     }
 }
@@ -235,14 +233,12 @@
 void
 transit_unintern (struct transit *transit)
 {
-  struct transit *ret;
-
   if (transit->refcnt)
     transit->refcnt--;
 
   if (transit->refcnt == 0)
     {
-      ret = hash_release (transit_hash, transit);
+      hash_release (transit_hash, transit);
       transit_free (transit);
     }
 }
@@ -552,10 +548,9 @@
 {
   struct attr attr;
   struct attr *new;
-  struct attr_extra *attre;
   
   memset (&attr, 0, sizeof (struct attr));
-  attre = bgp_attr_extra_get (&attr);
+  bgp_attr_extra_get (&attr);
   
   bgp_attr_default_set(&attr, origin);
 
@@ -1516,14 +1511,9 @@
         memcpy(&attr->nexthop.s_addr, &attre->mp_nexthop_global_in, 4);
       break;
     case 12:
-      {
-	u_int32_t rd_high;
-	u_int32_t rd_low;
-
-	rd_high = stream_getl (s);
-	rd_low = stream_getl (s);
-	stream_get (&attre->mp_nexthop_global_in, s, 4);
-      }
+      stream_getl (s); /* RD high */
+      stream_getl (s); /* RD low */
+      stream_get (&attre->mp_nexthop_global_in, s, 4);
       break;
 #ifdef HAVE_IPV6
     case 16: