Updated git submodules

Project: sdc/sdc-docker-base master 79dd5f998b4525a4cde5eefe5d8175f3b1f3a975

Add stretch repos to debian repo list

It appears that zlib1g=1:1.2.8.dfsg-5 has disappeared off of
the buster repos, and is now found in stretch repos.
Add the stretch repos so that this library version can be
installed.

libldap-2.4-2=2.4.45+dfsg-1 also disappeared and was
replaced with a different version.

Change-Id: Ifb1c83033e69d9b2343a262d3efa16007a30f89d
Issue-ID: SDC-1221
Issue-ID: SDC-1205
Signed-off-by: Gary Wu <gary.i.wu@huawei.com>

diff --git a/docs/submodules/sdc/sdc-docker-base.git b/docs/submodules/sdc/sdc-docker-base.git
index f539722..79dd5f9 160000 (submodule)
--- a/docs/submodules/sdc/sdc-docker-base.git
+++ b/docs/submodules/sdc/sdc-docker-base.git
@@ -1 +1 @@
-Subproject commit f5397220a48a770aa2ccca10ffb49a88621c74fa
+Subproject commit 79dd5f998b4525a4cde5eefe5d8175f3b1f3a975