build: update ICC warning CFLAGS

Intel's icc doesn't accept "-wd <number>" anymore, it's "-wd<number>"
these days.  But, anyhow, the warnings disabled in Quagga's configure.ac
don't seem to appear anywhere at all, so let's just remove the option
completely.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/configure.ac b/configure.ac
index fb6efd7..c1a4d8c 100755
--- a/configure.ac
+++ b/configure.ac
@@ -129,7 +129,7 @@
 if test "x${cflags_specified}" = "x" ; then
   case ${COMPILER} in
     "ICC")
-        CFLAGS="-Os -g -Wall -wd 279,869,981"
+        CFLAGS="-Os -g -Wall"
         AC_MSG_RESULT([Intel default])
         ;;
     "GCC")