<ticket>#639</ticket>
<ticket>#639</ticket>

gui/preferences.py:
- QPackagesWidget:
  Moved check if package is loaded from set_package_information
  to selected_enabled_list, so that it is not used for available
  packages.

VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,minesense/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,celiafish/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,hjanime/VisTrails,Nikea/VisTrails,celiafish/VisTrails,Nikea/VisTrails,Nikea/VisTrails,Nikea/VisTrails,minesense/VisTrails,VisTrails/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,celiafish/VisTrails,minesense/VisTrails,minesense/VisTrails