PAL distributions are vanilla Ubuntu, with a few custom packages in /opt/pal.
The OS_VERSION is set to the Ubuntu version suffixed with .PAL.

Adapt the few locations where a test on OS_VERSION == 16.04 or 18.04 is made,
to include 16.04% or 18.04% and match the .PAL suffix.

Affected packages by rename:
- pal-gazebo-plugins
- pal-gazebo-worlds
- pal-hardware-gazebo
- prf-roboticsgroup-gazebo-plugins
- py-talos-dev
- talos-data
- tiago-dev

And upgrade kinetic version to 2.6.9.

Changes in 2.6.9 (2019-11-05)
- Fix shadowed variables
- Contributors: Victor Lopez

Changed set force to set angle in gazebo underactuated finger plugin
Added gazebo world odometry that outputs rpy

It was not a dependency, and the package is osbsolete.