config

franka_description got updated with a more coarse collision model [1] matching the internal
self-collision detection, so the SRDF needs to be adapted.

Disable collision checking between panda_link6 and panda_link8 which collide in the default pose.
Tested with example controllers.

Closes #18. Resolves ros-planning/moveit#1210, resolves frankaemika/franka_ros#39.

[1] https://github.com/frankaemika/franka_ros/commit/e52c03a23aa18c6532e40f9bf4927dedfc0c596a