Update git submodules

* Update docs/submodules/compass4nfv from branch 'master'
  - Bug fix for tacker installation on centos7

    JIRA: -

    Currently there is no variable definition file of tacker
    for centos in os_tacker repo. This will lead an error
    while including vars on centos deployment. So this patch will
    add a file named "redhat-7.yml" for centos.

    Change-Id: I965834adb0d2d25e5a68a9c7dbb397342108078f
    Signed-off-by: Yifei Xue <xueyifei@huawei.com>

diff --git a/docs/submodules/compass4nfv b/docs/submodules/compass4nfv
index 45234f2..26f6569 160000 (submodule)
--- a/docs/submodules/compass4nfv
+++ b/docs/submodules/compass4nfv
@@ -1 +1 @@
-Subproject commit 45234f29eec45dc6a97c6a5db2a8d8a700624ab1
+Subproject commit 26f656961306239075612ac75a92b79db44e1539