ripd, isisd: fix warnings that make the build fail

These issues have been found by running buildtest.sh
using GCC 5.2.0 and Clang 3.7.0

Fixes pointer checks that can never be null

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Tested-by: NetDEF CI System <cisystem@netdef.org>
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/ripd/ripd.c b/ripd/ripd.c
index b708889..870873d 100644
--- a/ripd/ripd.c
+++ b/ripd/ripd.c
@@ -2574,7 +2574,7 @@
 
 	  if (IS_RIP_DEBUG_EVENT) 
 	    zlog_debug("SEND UPDATE to %s ifindex %d",
-		       (ifp->name ? ifp->name : "_unknown_"), ifp->ifindex);
+		       ifp->name, ifp->ifindex);
 
           /* send update on each connected network */
 	  for (ALL_LIST_ELEMENTS (ifp->connected, ifnode, ifnnode, connected))