Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Apex: add back legacy support for danube rpm"
  - Apex: add back legacy support for danube rpm

    Change-Id: I2f4a8c57bf056fcc266a0757b291309671ecc151
    Signed-off-by: Peng Liu <pliu@redhat.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 17d3243..5f4693d 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 17d3243b3d00b1707a511e500a89bb6e4448a37c
+Subproject commit 5f4693d46da0599ce67eadeb1eedd311ebc27699