Revert a111d47e9c

This caused FTBFS in knetworkmanager8

tools/dbusxml2qt3/methodgen.cpp

@@ -592,10 +592,6 @@ bool MethodGenerator::extractMethods(const TQDomElement& interfaceElement,
             {
                 method.async = hasAnnotation(element, "org.freedesktop.DBus.GLib.Async");
                 classData.methods.append(method);
-                if (method.async) {
-                    method.async = false;
-                    classData.methods.append(method);
-                }
             }
             else
                 classData.msignals.append(method);