execute: when recursively chowning StateDirectory= when spawning services, follow initial symlink

It should be OK to allow one level of symlink for the various types of
directories like StateDirectory=, LogsDirectory= and such.

src/test/test-chown-rec.c

@@ -104,7 +104,7 @@ TEST(chown_recursive) {
         assert_se(st.st_gid == gid);
         assert_se(has_xattr(p));
 
-        assert_se(path_chown_recursive(t, 1, 2, 07777) >= 0);
+        assert_se(path_chown_recursive(t, 1, 2, 07777, 0) >= 0);
 
         p = strjoina(t, "/dir");
         assert_se(lstat(p, &st) >= 0);