nixos/taskserver: Add a command to reload service

Unfortunately we don't have a better way to check whether the reload has
been done successfully, but at least we now *can* reload it without
figuring out the exact signal to send to the process.

Note that on reload, Taskserver will not reload the CRL file. For that
to work, a full restart needs to be done.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

nixos/modules/services/misc/taskserver/default.nix

@@ -454,6 +454,7 @@ in {
 
       serviceConfig = {
         ExecStart = "@${taskd} taskd server";
+        ExecReload = "${pkgs.coreutils}/bin/kill -USR1 $MAINPID";
         PermissionsStartOnly = true;
         User = cfg.user;
         Group = cfg.group;