nixos/sniproxy: remove unused logDir option

This never configured where SNI should log to, as it's up to the user to
provide the full sniproxy config (which can be configured to log to a
file).

This option only produced a ExecStartPre script that created the folder.

Let's use LogsDirectory to create it. In case users want to use another
directory for logs, they can override LogsDirectory or set their own
ExecStartPre script.

nixos/modules/services/networking/sniproxy.nix

@@ -14,6 +14,8 @@ let
 
 in
 {
+  imports = [ (mkRemovedOptionModule [ "services" "sniproxy" "logDir" ] "Now done by LogsDirectory=. Set to a custom path if you log to a different folder in your config.") ];
+
   options = {
     services.sniproxy = {
       enable = mkEnableOption "sniproxy server";
@@ -50,13 +52,6 @@ in
           }
         '';
       };
-
-      logDir = mkOption {
-        type = types.str;
-        default = "/var/log/sniproxy/";
-        description = "Location of the log directory for sniproxy.";
-      };
-
     };
 
   };
@@ -66,18 +61,12 @@ in
       description = "sniproxy server";
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
-      preStart = ''
-        test -d ${cfg.logDir} || {
-          echo "Creating initial log directory for sniproxy in ${cfg.logDir}"
-          mkdir -p ${cfg.logDir}
-          chmod 640 ${cfg.logDir}
-          }
-        chown -R ${cfg.user}:${cfg.group} ${cfg.logDir}
-      '';
 
       serviceConfig = {
         Type = "forking";
         ExecStart = "${pkgs.sniproxy}/bin/sniproxy -c ${configFile}";
+        LogsDirectory = "sniproxy";
+        LogsDirectoryMode = "0640";
         Restart = "always";
       };
     };