[PLYReader] Fix bad orientation & origin propreties

Fixes #626 

See [pcl::PLYReader::read](http://docs.pointclouds.org/trunk/classpcl_1_1_p_l_y_reader.html#ae44ab90c39f7077ad8a9b1646d95c301)

When `pcl::PLYReader::read` is called, the orientation & origin of the cloud are specified.
But without the fix, the value passed is modified and the `orientation_` proprety remains unmodified.

The same is happening with `origin` and `origin_`

Is that right @nizar-sallem ?