Fix gdm.GDM.find_by_content_type() (#668)
Fix gdm.GDM.find_by_content_type() (#668)

* Remove unused last_scan attribute of gdm.GDM

* Add missing documentation of entries attribute to gdm.GDM

* Fix gdm.GDM.find_by_content_type()
mjs7231/python-plexapi,pkkid/python-plexapi