Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Enable tempest

    Change-Id: I0fb12e4c2612f953998880a94b13655fa9ee0d8c
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 4ffe625..54aecdb 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 4ffe62585886f4a4e23a8e6f271f4de03eaeea10
+Subproject commit 54aecdbfe87a7148d16df951f5f2d0425b03aa24