Debian/Ubuntu pip default install to $HOME/.local

pip default install to $HOME/.local on Debian/Ubuntu

After pip 8.1.1-2 on Debian or Ubuntu you can pip install package without root user, which default to install to user home $HOME/.local.

The patch add logic that install user home while you not running virtualenv or root user, and it add a argument --system to overrides --user.

Debian patch

Github issue