Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "jumbo_frame: Add jumbo frame support"
  - jumbo_frame: Add jumbo frame support

    Add jumbo frame support for all packet forwarding applications
    inside guest for pxp testing. Enable jumbo frame support for
    OvsVanilla, OvsDpdkVhostUser, and Packet forwarding.

    Add minor fix for missing method issue when running packet
    forwarding tests. The get_version method was missing in
    the packet_forwaring core module.

    JIRA: VSPERF-501

    Change-Id: Ia99975f47c64259ed2566bde3c85b2779c309e80
    Signed-off-by: Christian Trautman <ctrautma@redhat.com>