Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/euphrates'
  - Merge "Remove argparse for adding argument -r" into stable/euphrates
  - Remove argparse for adding argument -r

    Change-Id: Iaa2ddc3f655a2bf85785a99a519e0df78c298037
    Signed-off-by: Linda Wang <wangwulin@huawei.com>
    (cherry picked from commit 240c496340d76be0a64726792de381d8fbc1db38)

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index df04735..f4629db 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit df047359248272e0fecf29a6b3a82fa906823640
+Subproject commit f4629db1b89e7a26663bd29408f2f8cd01ba68be