Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Merge "mount a ubuntu 16.04 image into qtip container"
  - mount a ubuntu 16.04 image into qtip container

    Downloading image time can be saved.

    Change-Id: I71de2cd14bdc0f279a75bfeffe959a603e8a7026
    Signed-off-by: zhihui wu <wu.zhihui1@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index d601cde..7caa49f 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit d601cde6a374d4e5b5138aab4cf4e156df5dbbc4
+Subproject commit 7caa49f07b45f24c22aeade51985bf8efbd6c222