Update git submodules

* Update docs/submodules/releng from branch 'master'
  - clean set-functest-env

     - remove useless parameters when calling download_images.sh
     - add traces

    Change-Id: Iecb3516b53e572ae93ba411fc9c23b691be26e69
    Signed-off-by: Morgan Richomme <morgan.richomme@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index ff4bea4..17ff086 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit ff4bea4e2b40ca32fd6921f2f560014dcb51fa3e
+Subproject commit 17ff08645fc8e6e8b2c0bc22152f2cab44d3f92b