Update git submodules

* Update docs/submodules/qtip from branch 'stable/danube'
  - Add missing license header

    Change-Id: Ifd9015b50ef05040b8eb90a3ad3e3edddfd61811
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>
    (cherry picked from commit 21a5c285f7b91bb78e2ec225104cd46201547216)

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index 818294f..a13ffed 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit 818294f56577a81f50325ca828451abf580fc8c5
+Subproject commit a13ffed7c69ae074d80d12152d267e6cf9954481