Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - Merge "xci: roles: configure-network: Avoid passing empty string to module"
  - xci: roles: configure-network: Avoid passing empty string to module

    The package module gets upset if we pass it an empty string as a package
    name

    Mar 09 15:15:33 TASK [configure-network : Ensure networking packages are present] **************
    Mar 09 15:15:49 fatal: [opnfv]: FAILED! => {"changed": false, "failed":
    true, "msg": "No package matching '' found available, installed or
    updated", "rc": 126, "results": ["iproute-3.10.0-87.el7.x86_64 providing
    iproute is already installed", "No package matching '' found available,
    installed or updated"]}

    As such, lets pass an existing package for non-Debian distros to make
    the module happy.

    Change-Id: Ib1128057097193278cfe50f79daf35332b54e781
    Signed-off-by: Markos Chandras <mchandras@suse.de>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 78e1ec9..5e2e518 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 78e1ec95b4b00de6451bbb495ab52f529fdb68ef
+Subproject commit 5e2e51892e73bbb71714fb2713d7c1abeb80bfdc