Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Remove style.css for License issue

    style.css is GPL 3.0 License based, we need to remove it.
    The origin css file is as bellow:
        https://www.opnfv.org/wp-content/themes/salient/style.css?ver=4.8.3

    So I remove style.css, and write a new css file to replace it.

    Change-Id: I78a572f74c71081052767622903b371e22e158a4
    Signed-off-by: grakiss <grakiss.wanglei@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 47d4daa..adedf4e 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 47d4daaa3df5c11462d698ff50c4dd2fe086d8d7
+Subproject commit adedf4e0a6e405ead72f004047c9c06cb7f90496