tools: use /usr/bin/python2.7 as the interpreter

tools: use /usr/bin/python2.7 as the interpreter

Distros such as Fedora
(https://fedoraproject.org/wiki/Packaging:Python#Multiple_Python_Runtimes
) are clamping down on python interpreter paths due to the desire to
switch to python3 so /usr/bin/python or /usr/bin/env python are no
longer liked. Unfortunately macOS doesn't ship a /usr/bin/python2 link
so switch all python interpreter paths to /usr/bin/python2.7 as a
compromise.

Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>