Remove line from later work.
Remove line from later work.

vistrails/core/upgradeworkflow.py:
  - remove get_vistrails_default_pkg_prefix import, to be added later

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