MNT : fix bug in qt5 event handling

Reported to the matplotlib-user mailing list

http://matplotlib.1069221.n5.nabble.com/Event-errors-in-qt5-backend-after-recent-commit-td44969.html

Fixes bug introduced in b72e0cd

The event and leave events were already being passed the gui event as those
handlers take no other arguments.

Author: tacaswell

lib/matplotlib/backends/backend_qt5.py

@@ -248,11 +248,11 @@ def __timerEvent(self, event):
         self.mpl_idle_event(event)
 
     def enterEvent(self, event):
-        FigureCanvasBase.enter_notify_event(self, event, guiEvent=event)
+        FigureCanvasBase.enter_notify_event(self, guiEvent=event)
 
     def leaveEvent(self, event):
         QtWidgets.QApplication.restoreOverrideCursor()
-        FigureCanvasBase.leave_notify_event(self, event, guiEvent=event)
+        FigureCanvasBase.leave_notify_event(self, guiEvent=event)
 
     def mousePressEvent(self, event):
         x = event.pos().x()