Remove extra action generation in "All Magics" menu population.

The function that populates "All Magics" and "CLASS magics" menus
used to create two separate QActions: one for the all-menu and one for class
menu. There is no apparent reason for doing that, since single QAction can
happily serve multiple menus and buttons.

IPython/qt/console/mainwindow.py

@@ -653,12 +653,8 b' class MainWindow(QtGui.QMainWindow):'
                     self,
                     triggered=self._make_dynamic_magic(pmagic)
                     )
-                xaction_all = QtGui.QAction(pmagic,
-                    self,
-                    triggered=self._make_dynamic_magic(pmagic)
-                    )
                 magic_menu.addAction(xaction)
-                self.all_magic_menu.addAction(xaction_all)
+                self.all_magic_menu.addAction(xaction)
 
     def update_all_magic_menu(self):
         """ Update the list of magics in the "All Magics..." Menu