Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Update tempest plugins tags

    Neutron and Barbican tempest plugins have just been released.

    Change-Id: Ib9c523e9a75dae31249fd84ba454d0ef8537ca1d
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
  - Switch from tempest section to openstack

    Rally warns from these deprecated conf sections.

    Change-Id: I15933c4f2cda14384e53202ec22f438a586d7b05
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
  - Move shaker and vmtp into functest-benchmarking

    It also updates all jobs and fixes Dockerhub hooks.

    Change-Id: Ib182155736b4dbdb829293081741a9d5cb8ea6d7
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
  - Update Xtesting to 0.60

    Xtesting leverages on stevedore [1] which will bring much more
    flexibility (discovery, module or class renaming, etc).

    OPNFV Features have to be updated as well:
      - https://gerrit.opnfv.org/gerrit/61713
      - https://gerrit.opnfv.org/gerrit/61715
      - https://gerrit.opnfv.org/gerrit/61717
      - https://gerrit.opnfv.org/gerrit/61719

    [1] https://docs.openstack.org/stevedore/latest/

    Change-Id: I0ce45eb6c9af66546c2c020eb962fa457f6c7e1a
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 57bd36e..d08554d 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 57bd36e426ef797cbc66f4031d612701671f7252
+Subproject commit d08554da5fd0e3c1119513ef2af6675df2488fe5