test: setup test data dir before fake runtime dir

That way, if the test directory does not exist we don't leave behind
temporary files (as in that case or on test failure the cleanup actions
don't run).

src/test/test-engine.c

@@ -37,10 +37,9 @@ int main(int argc, char *argv[]) {
         Job *j;
         int r;
 
-        assert_se(runtime_dir = setup_fake_runtime_dir());
-
         /* prepare the test */
         assert_se(set_unit_path(TEST_DATA_DIR("")) >= 0);
+        assert_se(runtime_dir = setup_fake_runtime_dir());
         r = manager_new(UNIT_FILE_USER, true, &m);
         if (MANAGER_SKIP_TEST(r)) {
                 log_notice_errno(r, "Skipping test: manager_new: %m");