Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Bugfix: No cirros-0.3.5-x86_64-disk.img"
  - Bugfix: No cirros-0.3.5-x86_64-disk.img

    JIRA: DOVETAIL-487

    1. Functest cvp.0.5.0 doesn't have cirros image in its docker container.
    2. Jobs need to download cirros-0.3.5-x86_64-disk.img and store it in
       $DOVETAIL_HOME/pre_config

    Change-Id: I12e4edb561ce21f813adc968d223fb0827529f7b
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 15c1408..117c48e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 15c1408286698d83d92e1b5ccfd159b783b6e50a
+Subproject commit 117c48ea667348525b8b8a35d8bc8e2f8067dcd5