Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  to 48d735cc1bec3b842d06a72992dc36c8799af381
  - Update all redirected links in Dovetail docs

    The pod ld-build2 only has python 3.6 installed, so change the tox env to be 3.6
    Other pods has python 3.5 to verify pep8, py35 ...

    Change-Id: I0289d7ce96ffa49dd08ce4b855fe071a5e608cbf
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 9b8d8fc..48d735c 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 9b8d8fcc9f4f191374f730b13fcb0ce18905864c
+Subproject commit 48d735cc1bec3b842d06a72992dc36c8799af381