Update git submodules

* Update docs/submodules/vswitchperf from branch 'stable/euphrates'
  - docs: Project description update

    Updated project description to clarify VSPERF independence from Open Stack

    Change-Id: Iab653c7ad1cf6cbdb9c15056337a2768a489a87a
    Signed-off-by: Trevor Cooper <trevor.cooper@intel.com>
    (cherry picked from commit bf1b0f81b1c79729433faa2bbf35a3cd7478066b)

diff --git a/docs/submodules/vswitchperf b/docs/submodules/vswitchperf
index 7397237..04c47a8 160000 (submodule)
--- a/docs/submodules/vswitchperf
+++ b/docs/submodules/vswitchperf
@@ -1 +1 @@
-Subproject commit 7397237867a5cd1ccc39c019c42c4048b80fc90e
+Subproject commit 04c47a891e038832702f4a6f868d15ed7e9160ab