Fix crash when placing cable plates (#534)

coil

2020-03-15 0e10e8360d6fa5aa6cbb86870b6244e8818d7dc8

Fix crash when placing cable plates (#534)

All coordinates can be equal if pointed_thing.above is identical
to pointed_thing.under.

 technic/machines/register/cables.lua

@@ -215,7 +215,7 @@
        if i == 1 then
            def.on_place = function(itemstack, placer, pointed_thing)
                local pointed_thing_diff = vector.subtract(pointed_thing.above, pointed_thing.under)
                local num
                local num = 1
                local changed
                for k, v in pairs(pointed_thing_diff) do
                    if v ~= 0 then
@@ -225,7 +225,7 @@
                    end
                end
                local crtl = placer:get_player_control()
                if (crtl.aux1 or crtl.sneak) and not (crtl.aux1 and crtl.sneak) then
                if (crtl.aux1 or crtl.sneak) and not (crtl.aux1 and crtl.sneak) and changed then
                    local fine_pointed = minetest.pointed_thing_to_face_pos(placer, pointed_thing)
                    fine_pointed = vector.subtract(fine_pointed, pointed_thing.above)
                    fine_pointed[changed] = nil