Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - xci: file: ansible-role-requirements: Bump SHA for rabbitmq-server

    The rabbitmq-server contains some fixes for SUSE so lets just bump this
    role instead of switching the entire OSA pin SHA so close to the Euphrates
    release.

    Change-Id: Ic034ed4bd9e290cadc5336d781b0e24036d5cd46
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 57fcda3..28436ea 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 57fcda3cebed64bfc1d5f85761cc3f24853641e7
+Subproject commit 28436eaa0771bd9fb290814960c7b74b2d928696