Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "xena2544_verify_fix: Fix Xena verify options"
  - xena2544_verify_fix: Fix Xena verify options

    Fixes issue when running multiple packets sizes and using the Xena
    verify option. Original values are restored to settings for each
    new packet size or test case.

    Also fixes a minor issue where if the test failed, the verify would
    run regardless.

    JIRA: VSPERF-515

    Change-Id: I6b6ce5160b66e7ed4a3847711c4f05529ae8ca54
    Signed-off-by: Christian Trautman <ctrautma@redhat.com>