Fixes erroneous return value
Fixes erroneous return value

Function returns bool, moreover -1 is True.

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