Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Fuel: adds retrieving OS credentials for MCP"
  - Fuel: adds retrieving OS credentials for MCP

    Adjusts retrieving OS credentials for MCP (master branch in fuel repo)

    Also removes legacy admin_ip and public_ip retrieving.

    Change-Id: Ib7781a3701c7281b781872b18150332b94298260
    Signed-off-by: Andrii Ostapenko <aostapenko@mirantis.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index abbf19f..a49f77e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit abbf19fc005ef6df0dcbba28d4bc8bd2a3365a41
+Subproject commit a49f77e37308ffc33d466240279000c607c9a94f