Back out "Don't run preSwitchChecks during install"

This backs out commit be2d9d7.

Author: Enzime

src/nixos-anywhere.sh

@@ -719,7 +719,7 @@ if [ ${copyHostKeys-n} = "y" ]; then
     cp -a "\$p" "/mnt/\$p"
   done
 fi
-NIXOS_NO_CHECK=1 nixos-install --no-root-passwd --no-channel-copy --system "$nixosSystem"
+nixos-install --no-root-passwd --no-channel-copy --system "$nixosSystem"
 if [[ ${phases[reboot]} == 1 ]]; then
   if command -v zpool >/dev/null && [ "\$(zpool list)" != "no pools available" ]; then
     # we always want to export the zfs pools so people can boot from it without force import