Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Merge "Add overview in developer guide"
  - Add overview in developer guide

    Change-Id: I491f921d87cf0cec3bbef5a78e9f3065b1e012a1
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index 252e6fc..e1797ec 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit 252e6fc6dd329b858dfc3773e42f52529ebe7659
+Subproject commit e1797ecb6ce4c2891204b8902079072734571122