Update git submodules

* Update docs/submodules/releng from branch 'master'
  to ab0490e0b3f8d9e815b716af0b3f17a244f2f4af
  - Pin virtualenv

    releng verify job (or the runner) is incompatible with
    latest virtualenv releases.

    Change-Id: I18cfc3414e5f278e47ae79df018dc27b698c30bc
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 928b92c..ab0490e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 928b92c635826366b213cbe2849508f6a108c8c2
+Subproject commit ab0490e0b3f8d9e815b716af0b3f17a244f2f4af