added the spec test on generic files to call the file content datastream twice
added the spec test on generic files to call the file content datastream twice

samvera/hyrax,ndlib/scholarsphere,jeremyf/sufia,ndlib/scholarsphere,zhang4952/scholarsphere,samvera/hyrax,jeremyf/sufia,zhang4952/scholarsphere,zhang4952/scholarsphere,samvera/hyrax,zhang4952/scholarsphere,samvera/hyrax,ndlib/scholarsphere