vm_trace.c: remove meaningless assingments

* vm_trace.c (call_trace_func): remove meaningless assingments to same
  variables.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36716 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

vm_trace.c

@@ -510,11 +510,7 @@ call_trace_func(rb_event_flag_t event, VALUE proc, VALUE self, ID id, VALUE klas
     int line = rb_sourceline();
     rb_thread_t *th = GET_THREAD();
 
-    if (klass != 0) {
-	id = id;
-	klass = klass;
-    }
-    else {
+    if (!klass) {
 	rb_thread_method_id_and_class(th, &id, &klass);
     }