Backport PR #3013: py3 workaround for reload in cythonmagic

closes  #3007

IPython/extensions/cythonmagic.py

@@ -20,6 +20,11 b' import os, sys'
 import imp
 
 try:
+    reload
+except NameError:   # Python 3
+    from imp import reload
+
+try:
     import hashlib
 except ImportError:
     import md5 as hashlib