tipc: Eliminate remaining support for routing table messages

Gets rid of all remaining code relating to ROUTE_DISTRIBUTOR messages.
These messages were only used in multi-cluster and multi-zone networks,
which TIPC no longer supports. (For safety, TIPC now treats such messages
the same way that it handles other unrecognized messages.)

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

net/tipc/link.c

@@ -1746,10 +1746,6 @@ deliver:
 						tipc_node_unlock(n_ptr);
 						tipc_link_recv_bundle(buf);
 						continue;
-					case ROUTE_DISTRIBUTOR:
-						tipc_node_unlock(n_ptr);
-						buf_discard(buf);
-						continue;
 					case NAME_DISTRIBUTOR:
 						tipc_node_unlock(n_ptr);
 						tipc_named_recv(buf);
@@ -1776,6 +1772,10 @@ deliver:
 							goto protocol_check;
 						}
 						break;
+					default:
+						buf_discard(buf);
+						buf = NULL;
+						break;
 					}
 				}
 				tipc_node_unlock(n_ptr);