Only check 3.3 for pathlib2 requirement

setup.py

@@ -212,7 +212,7 b' install_requires = ['
 # but requires pip >= 6. pip < 6 ignores these.
 
 extras_require.update({
-    ':python_version == "2.7" or python_version == "3.3"': ['pathlib2'],
+    ':python_version == "3.3"': ['pathlib2'],
     ':sys_platform != "win32"': ['pexpect'],
     ':sys_platform == "darwin"': ['appnope'],
     ':sys_platform == "win32"': ['colorama'],