Update git submodules

* Update docs/submodules/nfvbench from branch 'stable/euphrates'
  - Run tox at top level

    Change-Id: I3e72377554568020bd4730aaa4cfaf3294128a2e
    Signed-off-by: ahothan <ahothan@cisco.com>

diff --git a/docs/submodules/nfvbench b/docs/submodules/nfvbench
index a304887..8683295 160000 (submodule)
--- a/docs/submodules/nfvbench
+++ b/docs/submodules/nfvbench
@@ -1 +1 @@
-Subproject commit a304887b78e7d3d4786ecbe367c681d2f5d3926a
+Subproject commit 86832955f65bf9efdce512c35ff2e1074f45d370