Update git submodules

* Update docs/submodules/releng from branch 'master'
  - xci: Revert change moving prepare-functest to opnfv vm

    Change-Id: Ic9801a2f1282b695025a6dce70e662765ce4296b
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a89f725..a3c5676 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a89f725cd5192355555b36169aaaad76712de331
+Subproject commit a3c56768c819b1a8de6b69b19295038dd7a29bc3