added a note about an ad hoc comment-out

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@1036 e5f2f494-b856-4b98-b285-d166d9295462

src/lib/dns/cpp/rdata/generic/opt_41.cc

@@ -69,7 +69,7 @@ int
 OPT::compare(const Rdata& other) const
 {
     //const OPT& other_opt = dynamic_cast<const OPT&>(other);
-    dynamic_cast<const OPT&>(other);
+    dynamic_cast<const OPT&>(other); // right now we don't need other_opt
 
     return (0);
 }