Fixes #3967
Created by: dylanstrategie
I know N3X15's holy rage in smoothwall.dm is nice to read, even in light of his leaving, but this fix was harder to figure out than it should have been
- Fix relativewall_neighbours() bypassing current checks on update_icon() and allowing an unfinished reinforced wall to be -incorrectly- smoothed, leading to it looking finished
Should also act as a complete fail-safe to relativewall() being called on reinforced walls under construction
I shudder at the idea I could have been working with the old smoothwall code