Disable default cling-autoload callback (diag) for now.

The only real current user - ROOT - cannot make use of the diagnostics.
Instead the default callback should probably only be invoked if none of
the other, multiplexed handlers returns true.

lib/Interpreter/AutoloadCallback.cpp

@@ -45,8 +45,10 @@ namespace cling {
   }
 
   bool AutoloadCallback::LookupObject (TagDecl *t) {
+#if 0
     if (t->hasAttr<AnnotateAttr>())
       report(t->getLocation(),t->getNameAsString(),t->getAttr<AnnotateAttr>()->getAnnotation());
+#endif
     return false;
   }