Update git submodules

* Update docs/submodules/dovetail from branch 'master'
  - Replace openstack commands with shade

    Use openstack shade to get endpoint infomation rather than executing
    openstack commands directly.

    The next step can replace openstack commands by shade for some test cases that
    need to create openstack resources (images, flavors) if we agree to use shade.

    JIRA: DOVETAIL-659

    Change-Id: I72b302fb2d4a61e9249a7e53f81ea9464944dcd3
    Signed-off-by: xudan <xudan16@huawei.com>

diff --git a/docs/submodules/dovetail b/docs/submodules/dovetail
index 71f945d..4675432 160000 (submodule)
--- a/docs/submodules/dovetail
+++ b/docs/submodules/dovetail
@@ -1 +1 @@
-Subproject commit 71f945d3e3ca38e4a954a6475234e176e150d2f7
+Subproject commit 46754323aeac6193dd9b451a6525a478fdb0887b