Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[dovetail] Bugfix: incorrectly exit when file doesn't exist"
  - [dovetail] Bugfix: incorrectly exit when file doesn't exist

    When checking files, it shouldn't exit when getting an non-zero results.
    However, the scripts set -e at the begining.
    In order to continue the following steps when the file doesn't exists, replace
    all "return 0" or "return 1" to be "echo 0/1".

    Change-Id: I28ea81d52182d4dc5db56d47abbfbc1761f17d81
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index bede394..3f9fb3f 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit bede394dae3cc0f577a35a10880ea1f9fceeebbc
+Subproject commit 3f9fb3f3ad1bb8b56eaec535f11a523d3bfac4a2