Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "opnfvresultdb: Add mapping for VPP TCs"
  - opnfvresultdb: Add mapping for VPP TCs

    Patch adds testcase mapping among native VSPERF VPP TCs and appropriate
    TC names defined in results DB.

    JIRA: VSPERF-488

    Change-Id: I5c4a50587a354a741c738d255105726943a701f5
    Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
    Reviewed-by: Mars Toktonaliev <mars.toktonaliev@nokia.com>
    Reviewed-by: Morgan Richomme <morgan.richomme@orange.com>
    Reviewed-by: Al Morton <acmorton@att.com>
    Reviewed-by: Christian Trautman <ctrautma@redhat.com>
    Reviewed-by: Sridhar Rao <sridhar.rao@spirent.com>
    Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>

diff --git a/docs/submodules/vswitchperf b/docs/submodules/vswitchperf
index 3e22a01..2316473 160000 (submodule)
--- a/docs/submodules/vswitchperf
+++ b/docs/submodules/vswitchperf
@@ -1 +1 @@
-Subproject commit 3e22a019e196996230b47d91b9c3c4893656a3c6
+Subproject commit 231647397e9f359c11883e154620eae6b0a2cd15