Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Got an exception when test suite is empty

    1. Return empty test case list when test suite is empty.
    2. Don't quite understand why comment out all proposed_tests.
    3. Move stress ping test case at the end of the list,
       because it may broken the message queue.

    Change-Id: Ib717fc91e3763be03f243f82e53679462ecdae04
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 1f427c7..5ccacfe 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 1f427c7b74bec80deade3be3457fe3c4c16f75b5
+Subproject commit 5ccacfe4bc9ce4383ee3ef84f64fa620eae0d20f