Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "enable dovetail to run on APEX bgpvpn scenario"
  - enable dovetail to run on APEX bgpvpn scenario

    Since only APEX has the bgpvpn scenario in Euphrates, enable run dovetail
    on Apex euphrates scenario os-odl-bgpvpn-ha to test sdnvpn test cases.

    JIRA: DOVETAIL-568

    Change-Id: Ic7c880a5ef911fac17807e19484f937bdaa53e21
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index c8063f1..3f84461 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit c8063f1a9ed95e184fe93fdd61b0b537d83e7fce
+Subproject commit 3f84461f80baa8c0c039071678523e03e2d4651c