Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "Reduce complexity when using bifrost roles"
  - Reduce complexity when using bifrost roles

    We are using two variables which have a similar scope:
    - create_image_via_dib
    - use_prebuilt_images

    We could use one of them and not both. create_image_via_dib is selected
    because it also exists in upstream bifrost

    use_prebuilt_images = false is the same as create_image_via_dib = true
    use_prebuilt_images = true is the same as create_image_via_dib = false

    Change-Id: Ieaab78f1dc2d199746a2b13ebc82e9dc615d92e9
    Signed-off-by: Manuel Buil <mbuil@suse.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 94a953b..dba57fa 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 94a953b8d99377095b70ab5708d7c0eb9aefd784
+Subproject commit dba57fa5862e40cd005a0acd4679530a46c85d73