Update git submodules

* Update docs/submodules/releng from branch 'master'
  to f7df2d437f5b4b15d3c374da4d24b137cc672916
  - Add Jerma in blacklist logics

    https://build.opnfv.org/ci/job/functest-jerma-gate/5/

    Change-Id: I6f970f36256b5c07dea32f7cbb630e695eb226e0
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index b89957c..f7df2d4 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit b89957c233341f1e23b4a8359ca39a5bc7fd74e0
+Subproject commit f7df2d437f5b4b15d3c374da4d24b137cc672916