inputhookqt4: use InteractiveShell.instance instead of get_ipython

The latter is meant for user code only.

IPython/lib/inputhookqt4.py

@@ -16,6 +16,7 Author: Christian Boos
 # Imports
 #-----------------------------------------------------------------------------
 
+from IPython.core.interactiveshell import InteractiveShell
 from IPython.external.qt_for_kernel import QtCore, QtGui
 from IPython.lib.inputhook import allow_CTRL_C, ignore_CTRL_C, stdin_ready
 
@@ -56,7 +57,7 def create_inputhook_qt4(mgr, app=None):
             app = QtGui.QApplication([" "])
 
     # Re-use previously created inputhook if any
-    ip = get_ipython()
+    ip = InteractiveShell.instance()
     if hasattr(ip, '_inputhook_qt4'):
         return app, ip._inputhook_qt4