Update git submodules

* Update docs/submodules/compass4nfv from branch 'master'
  - Merge "Update the image tags to euphrates"
  - Update the image tags to euphrates

    JIRA: -

    Currently the latest tag is used in building tarball.
    As OPNFV Euphrates will be released soon, we change the
    tags of some docker images to euphrates.

    Change-Id: Ic7a746f3a3338cf7f5cacd2f932816b3776e7de6
    Signed-off-by: Yifei Xue <xueyifei@huawei.com>

diff --git a/docs/submodules/compass4nfv b/docs/submodules/compass4nfv
index 193dc21..42ddbcc 160000 (submodule)
--- a/docs/submodules/compass4nfv
+++ b/docs/submodules/compass4nfv
@@ -1 +1 @@
-Subproject commit 193dc2117a1fb96d9fdd98258c1040775a33f033
+Subproject commit 42ddbcc2fc6d091c1d137809343be63886822e5b