Update git submodules

Update git submodules

* Update docs/submodules/vswitchperf from branch 'master'
  - Merge "scapy: Load default SCAPY protocols"
  - scapy: Load default SCAPY protocols

    After the fix of SCAPY library import, it was not possible to use
    some of the network protocols by T-Rex. T-Rex 2.38 uses by default
    SCAPY 2.3.1 for python3, but it overrides the default set of network
    protocols loaded by layers/all.py. VSPERF makefile was modified to
    restore original version of all.py from SCAPY 2.3.1 git repository.
    Also examples of scapy usage were updated to generate correct traffic
    with modified scapy version.

    JIRA: VSPERF-566

    Change-Id: Ib9ae3c572e693e86d30eb0467ab9c812fe8f335b
    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>