nixos/prometheus-mail-exporter: misc fixes

- Fix misspelled option. mkRenamedOptionModule is not used because the
   option hasn't really worked before.
 - Add missing cfg.telemetryPath arg to ExecStart.
 - Fix mkdir invocation in test.

nixos/modules/services/monitoring/prometheus/exporters/mail.nix

@@ -90,7 +90,7 @@ let
         Timeout until mails are considered "didn't make it".
       '';
     };
-    disableFileDelition = mkOption {
+    disableFileDeletion = mkOption {
       type = types.bool;
       default = false;
       description = ''
@@ -147,6 +147,7 @@ in
       ExecStart = ''
         ${pkgs.prometheus-mail-exporter}/bin/mailexporter \
           --web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
+          --web.telemetry-path ${cfg.telemetryPath} \
           --config.file ${
             if cfg.configuration != null then configurationFile else (escapeShellArg cfg.configFile)
           } \

nixos/tests/prometheus-exporters.nix

@@ -224,7 +224,7 @@ let
           after = [ "postfix.service" ];
           requires = [ "postfix.service" ];
           preStart = ''
-            mkdir -p 0600 mail-exporter/new
+            mkdir -p -m 0700 mail-exporter/new
           '';
           serviceConfig = {
             ProtectHome = true;