Update git submodules

Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Merge "Fix dumping receive packets"
  - Fix dumping receive packets

    There were two issues identified in dump receive packets
    - when the receive packets was going to be dropped (and not transmitted),
      it was also printed as TX[255].
    - a potential crash when using the dump function with modes like
      lat which can receive more than MAX_RING_BURST.
    Those issues have been fixed.

    Change-Id: Ia2297539d64961a211389d68e3c9c6280472243c
    Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>