[CI] Disable ASF header checking on untracked files (apache#6975)

* This patch will disable checking for ASF header in untracked
  files that are never going to make its way into the repo.
* That would help developers to have their untracked local files.

Change-Id: Ie9f1aae28a474f10f52f22fe9e27a52afd95b4be

tests/scripts/task_lint.sh

@@ -31,7 +31,7 @@ echo "Checking file types..."
 python3 tests/lint/check_file_type.py
 
 echo "Checking ASF license headers..."
-tests/lint/check_asf_header.sh
+tests/lint/check_asf_header.sh --local
 
 echo "Linting the C++ code..."
 tests/lint/cpplint.sh