Fix DeprecationWarning for collections.Iterable import (#1417)

* Fix DeprecationWarning for collections.Iterable import

* Simplify version comparison

torchvision/datasets/lsun.py

@@ -5,7 +5,11 @@ import os.path
 import six
 import string
 import sys
-from collections import Iterable
+
+if sys.version_info < (3, 3):
+    from collections import Iterable
+else:
+    from collections.abc import Iterable
 
 if sys.version_info[0] == 2:
     import cPickle as pickle