Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Ignore Tox Error E722

    1. After updating tox from 2.5 to 2.9, pep8 failed.
    2. https://build.opnfv.org/ci/job/dovetail-verify-master/1018/console
    3. The Error is 'E722 do not use bare except'.
    4. It needs to change all 'except:' into 'except Exception:'.
    5. This won't affect Dovetail, so just ignore this Error.
    6. Dovetail next release will consider to fix this error.

    JIRA: DOVETAIL-537

    Change-Id: Ic3c7be4667685fc94025a47c3b17d07a087565da
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 529bc14..dc25f8f 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 529bc14bb2a255df72b5196ac70b5d1579c98eac
+Subproject commit dc25f8fac0ef4743943b55ba95c6971f07dc9af1