INCR-419 python3 compatibility

common/lib/conftest.py

@@ -1,11 +1,14 @@
 """Code run by pylint before running any tests."""
 
 # Patch the xml libs before anything else.
-from safe_lxml import defuse_xml_libs
-defuse_xml_libs()
+from __future__ import absolute_import
 
 import pytest
 
+from safe_lxml import defuse_xml_libs
+
+defuse_xml_libs()
+
 
 @pytest.fixture(autouse=True)
 def no_webpack_loader(monkeypatch):

common/lib/xmodule/setup.py

@@ -1,3 +1,5 @@
+from __future__ import absolute_import
+
 from setuptools import find_packages, setup
 
 XMODULES = [