Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Update modules/(test-)requirements"
  - Update modules/(test-)requirements

    It updates requirements.txt and test-requirements.txt according to
    OpenStack stable/ocata. It also fixes install_requires and
    test_requires in modules/setup.py.

    Change-Id: I9290db34e7bc1c78200130dd6a67d2d33dbc388d
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index fd24cfa..5407b66 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit fd24cfa3d91695bedf0b9d0c46ab9def833cf856
+Subproject commit 5407b668eecf4407b3f7d61003640323063cd32b