shorten-64-to-32 warning in qvector.h

..../include/QtCore/qvector.h:1016:26: warning: implicit conversion loses integer precision: 'long' to 'int' [-Wshorten-64-to-32]
               return n - d->begin();
               ~~~~~~ ~_^~~~~~~~~~~
..../include/QtCore/qvector.h:182:23: note: in instantiation of member function 'QVector
<Scriptable *>::indexOf' requested here
       const int i = indexOf(t);
                     ^