Code review comment for lp:~rsalveti/unity/phablet_adding_python_builddep

The ideal solution (from the distro perspective) would be to make it depend on python 3, but for that the line at ./tests/autopilot/CMakeLists.txt would need to be fixed as well.

As I'm not sure if we'd have an issue with autopilot when using python 3, I just added the build-dep on python2.7 to allow the shell to build again at the PPA (doesn't fail at jenkins as pbuild installs python2.7 by default).