Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/euphrates'
  - Merge "Title adjusted" into stable/euphrates
  - Title adjusted

    Removed Danube and simplified the title.

    Change-Id: I0029b87f5382acecd3dd8e143139920ffd57c696
    Signed-off-by: Sofia Wallin <sofia.wallin@ericsson.com>
    (cherry picked from commit 0646d553fe89a4cee686a59f3aa01a216cf7a0a5)

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index 5f53334..d7bd8e9 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit 5f53334001d69ce84c3ab155068b5bec700b698e
+Subproject commit d7bd8e9750d6dac28a71a7954795101ee0dd2896