Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "xci: Add common and OS family ansible var files"
  - xci: Add common and OS family ansible var files

    OS family vars_files are currently empty and put there to show
    the intend. (kind of TODO)

    opnfv.yml holds non-distro and non-flavor specific variables.

    Change-Id: I65aff2650257f2df00fd1f0a0638fd1aff596ac4
    Signed-off-by: Fatih Degirmenci <fatih.degirmenci@ericsson.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index b5f61c8..b5c5392 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit b5f61c88ae8e36755a4f79f04057c4bfec013a5e
+Subproject commit b5c5392388aab171c9eca9a97278234100a97cd3