Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Bugfix: the sdnvpn DB initialization information lacks two test cases

    1. The SDNVPN DB initialization information lacks two test cases,
       functest_testcase_4 and functest_testcase_8.
    2. So the results of these 2 test cases cannot be pushed into DB.
    3. Add these 2 test cases info to DB.

    JIRA: DOVETAIL-535

    Change-Id: I1c6d049b942806924f15dd106452fd9b4d554454
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 7825761..26276a2 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 78257613e55d1af14a5ce73f32859de0c9054bbf
+Subproject commit 26276a276dd37d2fbc7d26dc338613b928dbbfb3