Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add 'docker' string to functest docker build names"
  - Add 'docker' string to functest docker build names

    This will make it a little easier to track all our docker builds and
    clarify what these specific builds do.

    Change-Id: I92a60055af1153991877373550ea1a6f3e86682d
    Signed-off-by: Trevor Bramwell <tbramwell@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index ef537c1..174e24e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit ef537c1ebf7a46b884abb82f1e6a54483f07b93b
+Subproject commit 174e24e31c9b15b4b9d29656e261d38ac96f69a0