fix broken compile

tools/protobuf-compiler/src/main.rs

@@ -230,17 +230,12 @@ fn purge_out_dir(path: impl AsRef<Path>) {
          is expected to have read, write, execute permissions set",
         path.as_ref().display()
     );
-    for entry in read_dir(path).expect(read_dir_msg).flatten() {
+    for entry in read_dir(path).expect(&read_dir_msg).flatten() {
         // skip mod.rs as it's assumed to be the only non-generated file in the out dir.
-        if entry
-            .path()
-            .file_name()
-            .expect("every entry in the generated file out dir should have a name")
-            == "mod.rs"
-        {
+        if entry.path().file_name().expect(&entry_msg) == "mod.rs" {
             continue;
         }
 
-        std::fs::remove_file(entry.path()).expect(remove_msg);
+        std::fs::remove_file(entry.path()).expect(&remove_msg);
     }
 }