Fix use of python instead of python2 on linux.

[toastwaffle]

Due to Arch Linux's use of Python 3 as default, the /usr/bin/python symlink causes some things to fail. I've fixed it so that the python2 symlink is used, invoked through env instead of directly using the symlink, just in case some distro moves it. As far as I know, env is in a fixed position on every distro.