Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Refactor arch-specific Dockerfile patching"
  - Refactor arch-specific Dockerfile patching

    CHANGE: Obsolete "Dockerfile.aarch64" support,
    only "Dockerfile.$(uname -m).patch" mechanism is to be used
    from now on.

    It is correlated with https://gerrit.opnfv.org/gerrit/#/c/46797/

    Change-Id: If765550681d283dea7e3522f21080ea2c5e2fda4
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 3ade521..43a05d4 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 3ade521d53d4ed4fd8df232dff75a1869dc01e56
+Subproject commit 43a05d45f99d31c42a11578dce3f45c74745145d