extract: return if it fails to extract a file

src/main.rs

@@ -48,7 +48,8 @@ fn extract(input: PathBuf, output_directory: PathBuf)
 
         file_list.push(output_filename);
 
-        io::copy(&mut entry, &mut file);
+        io::copy(&mut entry, &mut file)
+            .map_err(|_| ())?;
     }
 
     Ok(file_list)