Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Merge "Update index page for docs.qtip.io"
  - Update index page for docs.qtip.io

    Change-Id: If6d64dc29cda08550f613eaaad097a5ff1f2815b
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index 58078e1..a4878f6 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit 58078e16491effb6b6264912b29a4f448571e8c6
+Subproject commit a4878f6c98855f5392324e0e72df3e2711022dd9