Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Fix the parameters of downloading"
  - Fix the parameters of downloading

    aria2c should use "-d" to indicate the directory to store the downloaded
    file.

    Change-Id: I6590403fb0c0b2938ee384cf5b1d5acc42ed94c1
    Signed-off-by: Alex Yang <yangyang1@zte.com.cn>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 29e0b0e..a8b0815 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 29e0b0ea6b5555045a7aad07d6c070967fbee355
+Subproject commit a8b0815ecb461830e204a51bca12e3ca4d837c98