Fix visibility of QVariant functions.

Change "Refactor QVariant handlers."
08863b6fda changed visibility of two
methods; QVariant::create and QVariant::cmp. These methods are internal
for Qt usage, but there is no need for breaking a dependent code.

Change-Id: Ic3a7f95dea5fa3e697f0686ae5d32dade24f14df
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>

src/corelib/kernel/qvariant.h

@@ -380,7 +380,7 @@ protected:
 #ifndef Q_NO_TEMPLATE_FRIENDS
     template<typename T>
     friend inline T qvariant_cast(const QVariant &);
-private:
+protected:
 #else
 public:
 #endif