View mode was changed before view when changing current vistrail
View mode was changed before view when changing current vistrail

Tab state was being reset before the view was changed, causing
the state to be stuck to either pipeline or version view when
switching between open vistrails.

gui/vistrails_window.py:
- change_view:
  call view_changed before resetting tab state

Bugfix: Wrong view mode when switching between open vistrails

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