Merge fort-nix/nix-bitcoin#520: secrets: fix sorting in setup-secrets

0ba6c63670 secrets: fix sorting in `setup-secrets` (Erik Arvstedt)

Pull request description:

ACKs for top commit:
  jonasnick:
    utACK 0ba6c63670

Tree-SHA512: f9bea9c3d73879c6450315d6c3f1920b1599b5a5875004cb6d6cb94d368362d79a0a23d7d2427711d548004eaac482145e7e732f531879dd049b14678f37a048

modules/secrets/secrets.nix

@@ -173,6 +173,10 @@ in {
          RemainAfterExit = true;
       };
       script = ''
+        # Use the same sort order for globbing and sorting as in Nix attrsets.
+        # Required for `comm` below.
+        export LC_COLLATE=C
+
         ${optionalString cfg.generateSecrets ''
           mkdir -p "${cfg.secretsDir}"
           cd "${cfg.secretsDir}"