Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - bugfix: Fix evaluation order of parameters

    This patch ensures, that testcase definition keywords vSwitch,
    Trafficgen, VNF and Tunnel Type will have the highest priority
    to override any values specified via ``Parameters`` section,
    CLI arguments or configuration files.

    JIRA: VSPERF-574

    Change-Id: Ied799187d489325a32cc4854145fdf9901e7e3e2
    Signed-off-by: Martin Klozik <martin.klozik@tieto.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: Richard Elias <richard.elias@tieto.com>