Update git submodules

* Update docs/submodules/releng from branch 'master'
  to c6f55934877797facb11dc79c684a9fc37ebeeba
  - Build functest-tempest if hutner and iruya

    Change-Id: Ic1def3037a3a5f474e9ba8a497a0425d6233e8af
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 958b9ea..c6f5593 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 958b9ea782ad7b8c6fbde821ed2e00eca031bbda
+Subproject commit c6f55934877797facb11dc79c684a9fc37ebeeba