[pkg] stop running 2to3

We can run natively on python3.3+ now.

setup.py

@@ -38,13 +38,6 @@ except ImportError:
     from distutils.command import install_lib
     USE_SETUPTOOLS = 0
 
-try:
-    # python3
-    from distutils.command.build_py import build_py_2to3 as build_py
-except ImportError:
-    # python2.x
-    from distutils.command.build_py import build_py
-
 sys.modules.pop('__pkginfo__', None)
 # import optional features
 __pkginfo__ = __import__("__pkginfo__")
@@ -161,8 +154,7 @@ def install(**kwargs):
                  scripts = ensure_scripts(scripts),
                  data_files = data_files,
                  ext_modules = ext_modules,
-                 cmdclass = {'install_lib': MyInstallLib,
-                             'build_py':    build_py},
+                 cmdclass = {'install_lib': MyInstallLib},
                  **kwargs
                  )