Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Add separate builders for Yardstick project jobs"
  - Add separate builders for Yardstick project jobs

    Added separate builders for Yardstick project jobs, in order
    to test each context individually. The new builders are:
      - Unit tests in Python 2.7
      - Unit tests in Python 3
      - Functional tests in Python 2.7
      - Functional tests in Python 3
      - Coverage tests
      - Style guidelines (PEP8) tests

    JIRA: YARDSTICK-877

    Change-Id: I625a956bdaad88277b6ba36852639f23c8cda198
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 348cc40..c7fdb45 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 348cc4049e931e8b72d56419562c7bead72121a1
+Subproject commit c7fdb455dcc51b5d56261f12b4169e899554139b