Fix broken build.x86_64-linux job (#573)
The job has been failing since https://hydra.nixos.org/eval/1461286
with the following error:
hydra-eval-jobs.cc:278:17: error: 'evalSettings' was not declared in this scope
evalSettings.restrictEval = true;
^~~~~~~~~~~~
This is likely due to a typo in 0882519 where that line and the
corresponding comment were moved, and `settings` was changed in that
one place to `evalSettings`.
I reproduced the error by running `nix-build release.nix -A
build.x86_64-linux` on my machine, and this small change fixes it.
