Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "Xena_Flow_Fix: Fixes multistream of greater than 64k values"
  - Xena_Flow_Fix: Fixes multistream of greater than 64k values

    Adds calculations to deal with values greater than 64k by doing
    a square root of the multistream value and using two mods
    to create the closet possible value that will work within the
    current implementation of multistream in VSPerf.

    JIRA: VSPERF-575

    Change-Id: I9dab4bbac094a394a11ed74fe2cd88fbe7079fc7
    Signed-off-by: Christian Trautman <ctrautma@redhat.com>