message: Update test_prior.launch
  Explicitly set g2o as optimizer
diff: <param name="RGBD/CreateOccupancyGrid" type="string" value="false"/>
  <param name="Optimizer/PriorsIgnored" type="string" value="false"/>
  + <param name="Optimizer/Strategy" type="string" value="1"/>
  <remap from="rgb/image" to="/camera/rgb/image_color"/>
  <remap from="depth/image" to="/camera/depth/image"/>
  