Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Dovetail tool replaces defcore with osinterop

    Rename the "defcore" test area to "osinterop".
    The DefCore working group has been
    renamed OpenStack InterOp Working Group some time ago.

    JIRA: DOVETAIL-499

    Change-Id: I144af767632c8fb83859e5e04b6427bb1a538348
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 8b79fa4..312db1d 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 8b79fa4a5e80a61224fd3805a7e2d1dd12b9c1a4
+Subproject commit 312db1d49ecfbefbb8b8795cfc1c2b58c07b711a