Correct ipv6InterfaceIdentifier of loopback device

Written-By: Jan Safranek <jsafrane@redhat.com>
Reviewed-By: Radek Vokal <rvokal@redhat.com>

Sent upstream as http://sourceforge.net/tracker/index.php?func=detail&aid=1783423&group_id=12694&atid=312694

--- net-snmp-5.3.1/agent/mibgroup/if-mib/data_access/interface_linux.c.orig	2007-08-23 18:06:31.000000000 +0200
+++ net-snmp-5.3.1/agent/mibgroup/if-mib/data_access/interface_linux.c	2007-08-23 18:06:47.000000000 +0200
@@ -674,6 +674,11 @@ netsnmp_arch_interface_container_load(ne
 
             entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_V6_IFID;
             break;
+            
+        case IANAIFTYPE_SOFTWARELOOPBACK:
+            entry->v6_if_id_len = 0;
+            entry->ns_flags |= NETSNMP_INTERFACE_FLAGS_HAS_V6_IFID;
+            break;
         }
 
         if (IANAIFTYPE_ETHERNETCSMACD == entry->type)