Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Fix openrc OS_CACERT for yardstick docker container

    The openrc should contain the path to OS_CACERT within container, not
    on opnfv vm.

    Change-Id: Ief4cb4ae647ff0f2cd4f3ebe8a2993bb71b0363f
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index f48050c..d4afa2b 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit f48050cbf6b761eba3b9f1d56e420ba3eebd6d64
+Subproject commit d4afa2b7ec9fd173055a0e9cc21314174eeb8c1b