src/bin/sage-notebook: Update for notebook 7

Author: Matthias Koeppe

src/bin/sage-notebook

@@ -29,7 +29,7 @@ class NotebookJupyter():
     def __init__(self, argv):
         self.print_banner()
         try:
-            from notebook.notebookapp import main
+            from notebook.app import main
         except ImportError:
             import traceback
             traceback.print_exc()