google-auth requirements.txt strange behavior

[randalpinto]

I currently run a python process inside of a container and we have a custom site-packages where all the requirements.txt are installed. All works fine until today when I tried to install "https://github.com/googleapis/google-auth-library-python". Here's the strange behaviour:

If I install google-auth via requirements.txt into my custom site-packages I get an error: ImportError: No module named google.oauth2.credentials

However if I install it as "pip install google-auth", in which case it gets installed to /usr/local/lib/python2.7/site-packages/ it works fine.

Any ideas?