[Linux] SMTK uses system python not superbuild python

The found python and python libs are pointing to /usr/bin/python2.7 & /usr/lib/x86_64-linux-gnu/libpython2.7.so

This causes problems because the UTF version of these builds of python differ than the one we build python with

OS details:

Distributor ID:	Ubuntu
Description:	Ubuntu 14.04.4 LTS
Release:	14.04
Codename:	trusty