Avoid variable shadowing in qobject_impl.h

Some people like to build their Qt-based projects with -Wshadow
-Werror, and since qobject_impl.h is included from a public Qt
header, their build breaks.

Change-Id: I5d8a5ee1937092149a18c0ff66a723f5bfc9ffc3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/kernel/qobject_impl.h

@@ -92,7 +92,7 @@ namespace QtPrivate {
     template <typename T>
     struct ApplyReturnValue {
         void *data;
-        ApplyReturnValue(void *data) : data(data) {}
+        ApplyReturnValue(void *data_) : data(data_) {}
     };
     template<typename T, typename U>
     void operator,(const T &value, const ApplyReturnValue<U> &container) {