Piglit began requiring Mako 0.7 as of commit ac1f382d "dispatch:
Generate piglit-dispatch from Khronos XML".
Piglit has required Mako for a long time, and CMake did check for Mako.
But CMake didn't check the version. This patch fixes CMake to require
Mako >= 0.7 and to provide the below hint on failure:
Hint: Try installing Mako with `pip install --user --upgrade Mako`
Reported-by: Tom Stellard <firstname.lastname@example.org>
Reviewed-by: Dylan Baker <email@example.com>
Signed-off-by: Chad Versace <firstname.lastname@example.org>