Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge changes from topics 'unittest_executor', 'import_absolute'

    * changes:
      impl executor and leverage to test_pod.py in TestAPI
      import from absolute path in TestAPI unit

  - impl executor and leverage to test_pod.py in TestAPI

    implement executor.py
    leverage executor to test_pod.py

    Change-Id: Ief70a28a935c86430e26f90f35112a7bab9fa81b
    Signed-off-by: SerenaFeng <feng.xiaowei@zte.com.cn>
  - import from absolute path in TestAPI unit

    Change-Id: Ic42db22d825229713b38c75c141af7742ca65dd3
    Signed-off-by: SerenaFeng <feng.xiaowei@zte.com.cn>