Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[builde servers] Update manifest-tool URL"
  - [builde servers] Update manifest-tool URL

    The fact returned for 'ansible_architecture' is 'x86_64' for non-ARM
    servers. Hard coding this now in order to pull the correct URL of the
    manifest tool.

    When arm build servers are included in this list we'll set a fact for
    the architecture needed in the URL.

    Change-Id: I1c89e8a87cc7f2ae386973f3f1088f881ae5df71
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 896d1ad..5f24ca3 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 896d1adf336fc0cafbbb8fe23a4e6c6d72338204
+Subproject commit 5f24ca33eae00da304d5a5ba2c023011128dfc7a