Don't set unidiff-zero anymore
Created by: eseliger
Discussion: Merge not required if we find reasons against it.
This was set for legacy reasons when we hand-crafted patches in the backend. Since we don't do that since campaigns changed drastically, and it can be unsafe, I think we can remove it at this point. @mrnugget I think you added that back then - WDYT, can we get rid of it?