Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Fix creds still used by vrouter

    1. 'CloudifyVrouter' object has no attribute 'creds'
    2. 'CloudifyVrouter' object was still use 'creds'
    3. Doing test of modified vyos_vrouter on our labs.

    Refer to following commit.
     https://gerrit.opnfv.org/gerrit/#/c/41249/

    Change-Id: Id1b4dfa4c35aba9bbb4fd64ef58446d3e99468df
    Signed-off-by: root <shuya.nakama@okinawaopenlabs.org>
    (cherry picked from commit 233a9bf775c1e9fe66e588ec45266c15bdb142b1)