Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Merge "HA testcases"
  - HA testcases

    Modify HA testcases.rst file to include detail discribtion of the 8
    testcases. Rename the original rst file into HA testcases outline.rst.
    Please review and see if you need two of these file, or you prefer a
    single one, or maybe merge these two.

    as discussed,propose 8 HA testcases for mandatory  test cases.

    JIRA:

    Change-Id: Ie6cd5a68897bb0208932d2e1fec65cc59bfa25b4
    Signed-off-by: fuqiao@chinamobile.com

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 3df2c61..2a4e39e 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 3df2c61b73f49cebf82d7d20041bf4231febbd59
+Subproject commit 2a4e39ee4abdbbadf1285a75fb5540a09432b5f4