backup: fix listDir to return path instead of fullPath

src/storage/interface.js

@@ -92,8 +92,8 @@ async function listDir(apiConfig, dir, batchSize, marker) {
     assert.strictEqual(typeof batchSize, 'number');
     assert(typeof marker !== 'undefined');
 
-    // Result: array of { fullPath, size }
-    // fullPath is relative to the dir being listed
+    // Result: array of { path, size }
+    // path is relative to the dir being listed
     throw new BoxError(BoxError.NOT_IMPLEMENTED, 'listDir is not implemented');
 }