title: QGraphicsObject with QPropertyAnimation in PyQt
body: <p>I have a strange bug with unworking QPropertyAnimation for a QGraphicsObject. Here is the code, Pyqt v.4.8.6, Qt 4.6. As you can see, there is no 'valueChanged' signal emitted.
  Is it a bug or what am i doing wrong? Thanks in advance!</p>
  
  <pre class="lang-py prettyprint-override"><code>import sys
  
  from PyQt4.QtGui import *
  from PyQt4.QtCore import *
  
  from functools import partial
  
  class GObject(QGraphicsObject): 
  
      def boundingRect(self): 
          return QRectF(0, 0, 10, 10)
  
      def paint(self, p, *args): 
          p.drawRect(self.boundingRect()) 
  
      def animatePos(self, start, end):
          print 'Animating..'
          anim = QPropertyAnimation(self, 'pos')
          anim.setDuration(400)
          anim.setStartValue(start)
          anim.setEndValue(end)
          self.connect(anim, SIGNAL('valueChanged(const QVariant&amp;)'), self.go)
          #self.connect(anim, SIGNAL('stateChanged ( QAbstractAnimation::State, QAbstractAnimation::State )'),self.ttt)
          anim.start( ) #QAbstractAnimation.DeleteWhenStopped)
  
      def go(self, t):
          print t
  
  class Scene_Chooser(QWidget):
      def __init__(self, parent = None):
          super(Scene_Chooser, self).__init__(parent)
  
          vbox = QVBoxLayout(self)
          vbox.setContentsMargins(0, 0, 0, 0)
          view = QGraphicsView(self)
          self.scene = QGraphicsScene(self) 
          obj = GObject() 
          self.scene.addItem(obj) 
          view.setScene(self.scene)
  
          btn = QPushButton('animate', self)
          vbox.addWidget(view)
          vbox.addWidget(btn)
          btn.clicked.connect(partial(obj.animatePos, QPointF(0,0), QPointF(10, 5)))
  </code></pre>