Fix regression introduced in e99c9f9e5f875aa9d416a1259d66a27ff725b902 causing --output to have no effect in GUI.
Fix regression introduced in e99c9f9e5f875aa9d416a1259d66a27ff725b902 causing --output to have no effect in GUI.

platsch/Slic3r,lordofhyphens/Slic3r,lordofhyphens/Slic3r,mcilhargey/Slic3r,platsch/Slic3r,alexrj/Slic3r,lordofhyphens/Slic3r,mcilhargey/Slic3r,curieos/Slic3r,lordofhyphens/Slic3r,tmotl/Slic3r,xoan/Slic3r,tmotl/Slic3r,mcilhargey/Slic3r,prusa3d/Slic3r,curieos/Slic3r,prusa3d/Slic3r,xoan/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,lordofhyphens/Slic3r,curieos/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,xoan/Slic3r,curieos/Slic3r,tmotl/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,prusa3d/Slic3r,pieis2pi/Slic3r,tmotl/Slic3r,pieis2pi/Slic3r,mcilhargey/Slic3r,platsch/Slic3r,mcilhargey/Slic3r,mcilhargey/Slic3r,mcilhargey/Slic3r,tmotl/Slic3r,xoan/Slic3r,curieos/Slic3r,xoan/Slic3r,platsch/Slic3r,alexrj/Slic3r,platsch/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,alexrj/Slic3r,pieis2pi/Slic3r,tmotl/Slic3r,prusa3d/Slic3r,xoan/Slic3r,platsch/Slic3r,alexrj/Slic3r,prusa3d/Slic3r,pieis2pi/Slic3r