Comment 9 for bug 810019

the issue also occurs with python-argparse installed:

$ mkdir -p external/argparse
$ touch external/__init__.py
$ echo "import argparse" > external/argparse/__init__.py
$ python -c "import external.argparse; import pkg_resources"
-c:1: UserWarning: Module argparse was already imported from /usr/lib/python2.7/argparse.pyc, but /usr/lib/python2.7/dist-packages is being added to sys.path