Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Merge "change the name of Yardstick results file and some log msg"
  - change the name of Yardstick results file and some log msg

    JIRA: DOVETAIL-428

    1. Change the name of Yardstick result file from opnfv_yardstick_tc019.out to
       dovetail.ha.tc001.out. Because opnfv_yardstick_tc019 is the name defined in
       Yardstick and dovetail.ha.tc001 is the name defined in Dovetail.
    2. Check whether the file exists before reporting the results are stored in file.
    3. Delete test cases vping_ssh, vping_userdata and sdnvpn.tc003 from the testsuite
       proposed_tests.

    Change-Id: I4cb16947729479616a03abd9e91b76f9a41a949c
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index ab4226e..8c6b453 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit ab4226ed3c39b8d7b759e93e05e27f1247763ec9
+Subproject commit 8c6b4532a230f6fbda2dd053ebadafaf7bbb6320