Python.user_site_packages: Ensure python exists [Linux] (#560)
Python.user_site_packages: Ensure python exists [Linux] (#560)

Fix the error:
brew info python
...
--HEAD
    Install HEAD version
sh: 1: python: not found
sh: 1: python: not found
==> Caveats
...
Linuxbrew/brew,hanxue/linuxbrew,hanxue/linuxbrew,Linuxbrew/brew,Linuxbrew/brew,maxim-belkin/brew,hanxue/linuxbrew,Linuxbrew/brew,maxim-belkin/brew,maxim-belkin/brew