GEOMESA-341 Confirm that export-to-Shapefile works as expected

Shapefiles were being written without geometry information. This is because Geotools requires that
the geometry attribute be named the_geom. The geometry attribute now gets renamed for shapefile export only.
Just to clear up my confusion...  Should 'q.setPropertyNames(overrideAttributes.get.split(','))' always run?  

Or should it run when (overrideAttributes.isDefined || config.attributes.isDefined) is true?