Comment 11 for bug 1573234

So the vtk6 change adds a new dependency, which makes pcl build with the system libproj. While switching pcl to the system libproj may be considered a significant change, nothing much actually uses pcl. The only reverse depends is ros-perception, which is the software this bug is attempting to fix in the first place, so I believe changing this is fine.

ACK on the debdiffs. I've uploaded vtk6 for processing by the SRU team.

Once it has been released, we can do the pcl no-change rebuild.