Ipv4RoutingTable: Removed deleting interface specific routes when an …

…interface goes down.

The routes must be deleted by the owner which originally added them to the routing table.
If the routes were added by a routing protocol, it is up to the routing protocol to delete them.

src/inet/networklayer/ipv4/Ipv4RoutingTable.cc

@@ -175,10 +175,7 @@ void Ipv4RoutingTable::receiveSignal(cComponent *source, simsignal_t signalID, c
         const auto *ieChangeDetails = check_and_cast<const NetworkInterfaceChangeDetails *>(obj);
         auto fieldId = ieChangeDetails->getFieldId();
         if (fieldId == NetworkInterface::F_STATE || fieldId == NetworkInterface::F_CARRIER) {
-            const auto *entry = ieChangeDetails->getNetworkInterface();
             updateNetmaskRoutes();
-            if (!entry->isUp() || !entry->hasCarrier())
-                deleteInterfaceRoutes(entry);
             invalidateCache();
         }
     }