Update git submodules

* Update docs/submodules/storperf from branch 'master'
  - Merge "Adding docker tag"
  - Adding docker tag

    Adds the tag to use when running docker from the DOCKER_TAG environment
    variable.

    Change-Id: Idde85510df01f8a809049dac62872db0c8a5bf25
    JIRA: STORPERF-128
    Signed-off-by: mbeierl <mark.beierl@dell.com>

diff --git a/docs/submodules/storperf b/docs/submodules/storperf
index 8f3c685..9c45fac 160000 (submodule)
--- a/docs/submodules/storperf
+++ b/docs/submodules/storperf
@@ -1 +1 @@
-Subproject commit 8f3c6859e483961fd9740bb662bbd049b512bba2
+Subproject commit 9c45fac0bbe4f32c1c6baea0ed27c351fe757ae8