Fix typo that causes non-flake builds to fail

Author: r-vdp

terraform/nix-build/nix-build.sh

@@ -4,7 +4,7 @@ set -efu
 declare file attribute nix_options
 eval "$(jq -r '@sh "attribute=\(.attribute) file=\(.file) nix_options=\(.nix_options)"')"
 options=$(echo "${nix_options}" | jq -r '.options | to_entries | map("--option \(.key) \(.value)") | join(" ")')
-if [[ -n ${file-} ]] && [[ -e ${fileh-} ]]; then
+if [[ -n ${file-} ]] && [[ -e ${file-} ]]; then
   # shellcheck disable=SC2086
   out=$(nix build --no-link --json $options -f "$file" "$attribute")
   printf '%s' "$out" | jq -c '.[].outputs'