Update pcl depends

[efernandez]

This fixes the following error when running rosdep install --from-paths src -iy from the workspace with scan_tools:

ERROR: the following packages/stacks could not have their rosdep keys resolved
to system dependencies:
scan_to_cloud_converter: Cannot locate rosdep definition for [pcl]
laser_ortho_projector: Cannot locate rosdep definition for [pcl]
laser_scan_matcher: Cannot locate rosdep definition for [pcl]

[130s]

@efernandez I assume this PR is targeted for post-Hydro distros where pcl as a package got unavailable?

[ubuntuslave]

I can't test this since I'm still running fuerte on my laptops. @130s can you please see if the pcl dependency fix given by @efernandez works in the indigo and hydro branches?

[130s]

I confirmed that this PR:

• works on Indigo

• solves a problem on Hydro too. Without this PR, rosdep fails:

  $ sudo apt-get purge ros-hydro-pcl*
  $ rosdep install --from-paths src --ignore-src --rosdistro hydro -y
  ERROR: the following packages/stacks could not have their rosdep keys resolved
  to system dependencies:
  scan_to_cloud_converter: Cannot locate rosdep definition for [pcl]
  laser_ortho_projector: Cannot locate rosdep definition for [pcl]
  laser_scan_matcher: Cannot locate rosdep definition for [pcl]
  

Therefore +1, and I'm merging. I'll cherry-pick into branches too.

[efernandez]

Thanks!