Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Stop redefine testcases.yaml for some test cases

    1. For Functest healthcheck, patrole, refstack_defcore, neutron_trunk and vping
       test cases, stop to redefine testcases.yaml.
    2. For VNF and bgpvpn, they still have scenario dependencies for Functest.
       How to handle them are still under consideration.
    3. For other tempest test cases, they rely on tempest_custom. Leave them
       under discussion.

    JIRA: DOVETAIL-673

    Change-Id: Ibd10c9883d8df3749f4a93e280deaca77fe6bc00
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index a017201..7cd5c4c 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit a017201e115d27c86a00959e7baedbb0c95f0580
+Subproject commit 7cd5c4c60b3f9a9893c2801a39061489ecfa6ae0