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/zclient.c b/lib/zclient.c
index a5d5b7f..5815eaa 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -816,7 +816,6 @@
 static int
 zclient_read (struct thread *thread)
 {
-  int ret;
   size_t already;
   uint16_t length, command;
   uint8_t marker, version;
@@ -911,47 +910,47 @@
     {
     case ZEBRA_ROUTER_ID_UPDATE:
       if (zclient->router_id_update)
-	ret = (*zclient->router_id_update) (command, zclient, length);
+	(*zclient->router_id_update) (command, zclient, length);
       break;
     case ZEBRA_INTERFACE_ADD:
       if (zclient->interface_add)
-	ret = (*zclient->interface_add) (command, zclient, length);
+	(*zclient->interface_add) (command, zclient, length);
       break;
     case ZEBRA_INTERFACE_DELETE:
       if (zclient->interface_delete)
-	ret = (*zclient->interface_delete) (command, zclient, length);
+	(*zclient->interface_delete) (command, zclient, length);
       break;
     case ZEBRA_INTERFACE_ADDRESS_ADD:
       if (zclient->interface_address_add)
-	ret = (*zclient->interface_address_add) (command, zclient, length);
+	(*zclient->interface_address_add) (command, zclient, length);
       break;
     case ZEBRA_INTERFACE_ADDRESS_DELETE:
       if (zclient->interface_address_delete)
-	ret = (*zclient->interface_address_delete) (command, zclient, length);
+	(*zclient->interface_address_delete) (command, zclient, length);
       break;
     case ZEBRA_INTERFACE_UP:
       if (zclient->interface_up)
-	ret = (*zclient->interface_up) (command, zclient, length);
+	(*zclient->interface_up) (command, zclient, length);
       break;
     case ZEBRA_INTERFACE_DOWN:
       if (zclient->interface_down)
-	ret = (*zclient->interface_down) (command, zclient, length);
+	(*zclient->interface_down) (command, zclient, length);
       break;
     case ZEBRA_IPV4_ROUTE_ADD:
       if (zclient->ipv4_route_add)
-	ret = (*zclient->ipv4_route_add) (command, zclient, length);
+	(*zclient->ipv4_route_add) (command, zclient, length);
       break;
     case ZEBRA_IPV4_ROUTE_DELETE:
       if (zclient->ipv4_route_delete)
-	ret = (*zclient->ipv4_route_delete) (command, zclient, length);
+	(*zclient->ipv4_route_delete) (command, zclient, length);
       break;
     case ZEBRA_IPV6_ROUTE_ADD:
       if (zclient->ipv6_route_add)
-	ret = (*zclient->ipv6_route_add) (command, zclient, length);
+	(*zclient->ipv6_route_add) (command, zclient, length);
       break;
     case ZEBRA_IPV6_ROUTE_DELETE:
       if (zclient->ipv6_route_delete)
-	ret = (*zclient->ipv6_route_delete) (command, zclient, length);
+	(*zclient->ipv6_route_delete) (command, zclient, length);
       break;
     default:
       break;