Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[dovetail] Querying correct control node IPs"
  - [dovetail] Querying correct control node IPs

    The parameter used to query the host IPs of the database and message
    queue hosts was wrong, resulting in the corresponding HA tests to fail.

    Change-Id: I460209c63928ac99d5449adba03474fdf066ebcf
    Signed-off-by: Georg Kunz <georg.kunz@ericsson.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 525aa95..15acdc0 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 525aa95f876fe68385ad09bce6a2865003669f9f
+Subproject commit 15acdc032983c58d3e7de94143e08ad1880bacee