Fixed avoiding of other printed objects
Fixed avoiding of other printed objects

Calling std::move on itself causes that the first polygon is empty, which results in disabling this feature

prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r