Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "update installer under scenario"
  - update installer under scenario

    1. post, add one or more new installers
    2. update, replace existed installers as a totality
    3. delete, delete one or more installers by name
    4. in post&update, if schema is not consistent with ScenarioInstaller model,
    BadRequest will be raised(only extra keys will be detected currently)
    5. in post, if installer already exist, return Conflict with already exist
    message
    6. in update, if a installer appears more than once, also return Conflict
    with already exist message

    Change-Id: I830dba3bcf5f1a9d1c93513b4aae59009f69dc8f
    Signed-off-by: SerenaFeng <feng.xiaowei@zte.com.cn>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a45e3e9..2a46ee4 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a45e3e956f9a23ec963318f56575974e1a755c93
+Subproject commit 2a46ee4c60e3eeb95311cf406a9bef71d2d66777