Revert "nixos/systemd: Handle template overrides"

This reverts commit e3b90b6ccc.

This commit broke container tests and thus blocked channels from
advancing.

nixos/modules/system/boot/systemd-lib.nix

@@ -182,18 +182,7 @@ in rec {
       # upstream unit.
       for i in ${toString (mapAttrsToList (n: v: v.unit) units)}; do
         fn=$(basename $i/*)
-
+        if [ -e $out/$fn ]; then
-        case $fn in
-          # if file name is a template specialization, use the template's name
-          *@?*.service)
-            # remove @foo.service and replace it with @.service
-            ofn="''${fn%@*.service}@.service"
-            ;;
-          *)
-            ofn="$fn"
-        esac
-
-        if [ -e $out/$ofn ]; then
           if [ "$(readlink -f $i/$fn)" = /dev/null ]; then
             ln -sfn /dev/null $out/$fn
           else

nixos/tests/systemd-template-override.nix

@@ -1,41 +0,0 @@
-import ./make-test-python.nix {
-  name = "systemd-template-override";
-
-  machine = { pkgs, lib, ... }: let
-    touchTmp = pkgs.writeTextFile {
-      name = "touch-tmp@.service";
-      text = ''
-        [Service]
-        Type=oneshot
-        ExecStart=${pkgs.coreutils}/bin/touch /tmp/%I
-      '';
-      destination = "/etc/systemd/system/touch-tmp@.service";
-    };
-  in {
-    systemd.packages = [ touchTmp ];
-
-    systemd.services."touch-tmp@forbidden" = {
-      serviceConfig.ExecStart = [ "" ''
-        ${pkgs.coreutils}/bin/true
-      ''];
-    };
-
-    systemd.services."touch-tmp@intercept" = {
-      serviceConfig.ExecStart = [ "" ''
-        ${pkgs.coreutils}/bin/touch /tmp/renamed
-      ''];
-    };
-  };
-
-  testScript = ''
-    machine.wait_for_unit("default.target")
-
-    machine.succeed("systemctl start touch-tmp@normal")
-    machine.succeed("systemctl start touch-tmp@forbbidden")
-    machine.succeed("systemctl start touch-tmp@intercept")
-
-    machine.succeed("[ -e /tmp/normal ]")
-    machine.succeed("[ ! -e /tmp/forbidden ]")
-    machine.succeed("[ -e /tmp/renamed ]")
-  '';
-}