Quick Fix:
I just got around what I think was the same problem. You might consider trying this (sudo, if necessary):
pip install scrape --upgrade --ignore-installed six
Github is ultimately where I got this answer (and there are a few more suggestions you may consider if this one doesn’t solve your problem). It also seems as though this is an El Capitan problem.
Also, this technically might be a duplicate. But the answer the other post came up with was installing your own Python rather than relying on the default osx Python, which strikes me as more laborious.
Longer, Real Fix:
Eventually I ran into a situation where I actually needed to upgrade six in order to install some other libraries, at which point ignoring wasn’t enough. The easiest way to upgrade six for me was to not use pip, but instead to manually download the .tar.gz from the six page, decompress, move to the newly decompressed six package directory, and run the installation manually (sudo, if necessary):
python setup.py install
Thanks to this answer for the guidance.