Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Fix bug in running storperf.sh when WORKSPACE is defined

    When working directory changes, the script and default configuration
    will not be found.

    Change-Id: Iab6e4f9b014c12a863498de42553b043357aa876
    Signed-off-by: Yujun Zhang <zhang.yujunz@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index f708300..c420248 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit f708300052c2315994ba16793972ce0dfbfa237e
+Subproject commit c420248ac1daed625ab0d05d1a663c877426701a