Update git submodules

* Update docs/submodules/compass4nfv from branch 'master'
  - Workaround for Tacker in HA scenarios

    JIRA: -

    For Tacker service in HA mode, it only generates VIM fernet key on
    one of the Tacker hosts. This may cause error when a request is
    been routed to another host. We need to use Barbican and Mistral
    components. But now OSA did not support Mistral yet. So we add
    a workaround here to get over this issue.

    Change-Id: I9aa228ec2ac7011cedb1eb503611ca24c7666caa
    Signed-off-by: Yifei Xue <xueyifei@huawei.com>

diff --git a/docs/submodules/compass4nfv b/docs/submodules/compass4nfv
index 39d0f4c..d7156c0 160000 (submodule)
--- a/docs/submodules/compass4nfv
+++ b/docs/submodules/compass4nfv
@@ -1 +1 @@
-Subproject commit 39d0f4c45d616f8c5bce7ca8db900a66705f439b
+Subproject commit d7156c0b772ada65ff3d094bd70814bf5b0cb4e7