nixos/tests/gitdaemon: fix user and group

- change tmpfiles rule user/group to default daemon user/group set by
gitDaemon module - git:git
- add chown of created repo to user/group of daemon after local subtest
on server (that run from root user) pass. Without it next subtest doing
clone from remote fails with "detected dubious ownership in repository"
on server side.

nixos/tests/gitdaemon.nix

@@ -20,7 +20,7 @@ in {
 
         systemd.tmpfiles.rules = [
           # type path mode user group age arg
-          " d    /git 0755 root root  -   -"
+          " d    /git 0755 git  git   -   -"
         ];
 
         services.gitDaemon = {
@@ -56,6 +56,10 @@ in {
             "rm -r /project",
         )
 
+    # Change user/group to default daemon user/group from module
+    # to avoid "fatal: detected dubious ownership in repository at '/git/project.git'"
+    server.succeed("chown git:git -R /git/project.git")
+
     with subtest("git daemon starts"):
         server.wait_for_unit("git-daemon.service")