Fixes the build with base GCC.

commit b84f08c8b7c91a979bd74840561af2391ef20666
Author: Lars Knoll <lars.knoll@digia.com>
Date:   Tue May 6 13:30:31 2014 +0200

    Fix compiler warning

    Change-Id: I26df4f1b8417c6b075d81eaf118669a4103503e2
    Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

--- src/qml/jsruntime/qv4object_p.h
+++ src/qml/jsruntime/qv4object_p.h
@@ -168,7 +168,8 @@ struct Q_QML_EXPORT Object: Managed {
     void defineReadonlyProperty(const StringRef name, ValueRef value);
 
     void insertMember(const StringRef s, const ValueRef v, PropertyAttributes attributes = Attr_Data) {
-        insertMember(s, Property(*v), attributes);
+        Property p(*v);
+        insertMember(s, p, attributes);
     }
     void insertMember(const StringRef s, const Property &p, PropertyAttributes attributes);