Update git submodules

* Update docs/submodules/qtip from branch 'stable/danube'
  - Merge "add qtip installation in Dockerfile" into stable/danube
  - add qtip installation in Dockerfile

    Docker build successfully on local. And QTIP cli works well.

    Change-Id: I0916c73e67808ae170ff7b290b8e03b605be8e69
    Signed-off-by: wu.zhihui <wu.zhihui1@zte.com.cn>
    (cherry picked from commit 8c325e64ada6fb2cb4377e592fa204170c7d8513)

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index c1e6c49..686c702 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit c1e6c491704060090c376e8839c7a02c6da10a79
+Subproject commit 686c7023613491a99c8e2ada758edb720655a6e6