Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Update logger via logging.getLogger()

    1. The module functest.utils.functest_logger has been deleted and
       logger has been reconfigured in functest [1].
    2. Update all related modules to get loggers via logging.getLogger().

    [1] https://gerrit.opnfv.org/gerrit/#/c/34019/

    JIRA: FUNCTEST-824

    Change-Id: I89f5d15342b5f257fbc2700655e255a4e28bd36f
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/sdnvpn b/docs/submodules/sdnvpn
index dc24635..93370e8 160000 (submodule)
--- a/docs/submodules/sdnvpn
+++ b/docs/submodules/sdnvpn
@@ -1 +1 @@
-Subproject commit dc24635f0e1cb103c333f8b614a4801341b4f877
+Subproject commit 93370e86515f9381ec84f9408a2bf900a0ed8689