Add Python 2.7.9

I'll take a stab at this...
It's necessary to install `pip` during `pyenv install`. Adding `ensurepip` runs `python -m ensurepip` after building of CPython.

https://github.com/yyuu/pyenv/blob/db6a41c90fd028889bd781347f26af27a7ea4e69/plugins/python-build/bin/python-build#L1501