zap the _pdborg suffix when loading entities from pdb.org

PDB is the de-facto standard when loading structures remotely
and shouldn't require any suffix.

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2664 5a81b35b-ba03-0410-adc8-b2c5c5119f08