Fix to if test

IPython/html/services/notebooks/filenbmanager.py

@@ -100,7 +100,7 b' class FileNotebookManager(NotebookManager):'
             full_path = self.get_path(notebook_name, notebook_path)
             if change == "name":
                 new_path = self.get_path(data['name'], notebook_path)
-                if os.path.isfile(new_path) == False:
+                if not os.path.isfile(new_path):
                     os.rename(full_path,
                         self.get_path(data['name'], notebook_path))
                     notebook_name = data['name']