Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Removing test_mtu_sized_frames Tempest test

    This test fails in CI on all installers (Apex, Compass, Fuel) and on
    virtual deployments.

    Change-Id: I3a451e880c2a5d2151cb88aaf8e5a6895368e63b
    Signed-off-by: Georg Kunz <georg.kunz@ericsson.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 6d45697..a43b9f9 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 6d45697ac15a71300752256515625f03a8808389
+Subproject commit a43b9f9fe0416e2213f0994b6b57ffb957360e6a