Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Conform with Barbican gates

    tempest.conf conforms with Devstack post-actions [1].

    One test is still disabled as it may force to sign all images.
    A deeper analysis has to be done before enabling it.

    [1] https://github.com/openstack/barbican-tempest-plugin/blob/master/tools/pre_test_hook.sh

    Change-Id: I163c0e7c4671ca67f0b6c127c29fdcb12a8e426b
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>