Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: infra: bifrost: Make sure XCI variables are defined first

    It's best to define all the XCI variables before everything else
    to ensure that all subsequent bifrost variables are properly
    defined.

    Change-Id: Id4a9e0c89e8dd32b852cfef6b9bb336c4b75f5a7
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 90cce1c..17eb953 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 90cce1c977844b134ba90f89eefcf3d2ac12c5fc
+Subproject commit 17eb953055bee3ae828ab839ec1bca5e28189222