Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - docs: Remove whitespaces from indexes

    Whitespaces were removed from RST indexes to correctly
    pass rst validation.

    Change-Id: I5f277d5f8846653c6e7ea3fbb29881e2dd3f610b
    Signed-off-by: Martin Klozik <martinx.klozik@intel.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>