Update git submodules

* Update docs/submodules/storperf from branch 'stable/euphrates'
  - Improving Reporting

    Changes IOPS and BW to summation vs. average.
    Adds fixed 0 y axis to all graphs

    Change-Id: I3379597bda04b030424a25c7309a02c982fdb706
    Signed-off-by: mbeierl <mark.beierl@dell.com>
    (cherry picked from commit 31b0e130755cbd425b26f740e5701768d77f98f0)

diff --git a/docs/submodules/storperf b/docs/submodules/storperf
index c7c303e..7cafd2b 160000 (submodule)
--- a/docs/submodules/storperf
+++ b/docs/submodules/storperf
@@ -1 +1 @@
-Subproject commit c7c303ecc18fd1d7b92b60db5eaca42f67e6204c
+Subproject commit 7cafd2b79cf1d83c9bddb6b7c686b693ad84a5e4