Update git submodules

* Update docs/submodules/qtip from branch 'master'
  - Merge "refactor: run storperf scripts in qtip container"
  - refactor: run storperf scripts in qtip container

    The preious storperf scripts can only be run based on the host.
    This patch will make them run in qtip container.

    JIRA: QTIP-248

    README.md will tell you how to use these scripts.

    Change-Id: I4d2d51f859499e6e56ae8692d880cbde27297b82
    Signed-off-by: zhihui wu <wu.zhihui1@zte.com.cn>

diff --git a/docs/submodules/qtip b/docs/submodules/qtip
index 72f2521..2a91ca1 160000 (submodule)
--- a/docs/submodules/qtip
+++ b/docs/submodules/qtip
@@ -1 +1 @@
-Subproject commit 72f2521a18aeed7aa3485f98b15eaa325deafa18
+Subproject commit 2a91ca171b2c6defe5ce4ec23426d3140e4572cf