Resolve needless_borrow pedantic clippy lint in test

    error: the borrowed expression implements the required traits
      --> tests/data/lib.rs:36:31
       |
    36 |     for entry in fs::read_dir(&yaml_test_suite).unwrap() {
       |                               ^^^^^^^^^^^^^^^^ help: change this to: `yaml_test_suite`
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
       = note: `-D clippy::needless-borrow` implied by `-D clippy::all`

tests/data/lib.rs

@@ -33,7 +33,7 @@ fn test(ignorelist: &str, check: fn(&Path) -> bool) -> TokenStream {
 
     let mut ids = Map::new();
     let yaml_test_suite = tests_dir.join("data").join("yaml-test-suite");
-    for entry in fs::read_dir(&yaml_test_suite).unwrap() {
+    for entry in fs::read_dir(yaml_test_suite).unwrap() {
         let entry = entry.unwrap();
         if !entry.file_type().unwrap().is_dir() {
             continue;