Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "fuel: remove the trigger on zte pod2"
  - fuel: remove the trigger on zte pod2

    zte pod2 will be provided to daisy to run CI job.

    Change-Id: I9e0eee1bab4a949f6434850dcbd9624ac6476344
    Signed-off-by: wu.zhihui <wu.zhihui1@zte.com.cn>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a3e8793..6ac9920 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a3e87931c488c6f39e323f81573473accb4adfab
+Subproject commit 6ac992092847f5fa45fa5178bd7e57b5a2b572e8