Update git submodules

Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Merge "Initial support for DPDK 18.05"
  - Initial support for DPDK 18.05

    This patch makes PROX compile with DPDK 18.05.
    However some features are disabled or will not work as expected
    such as:
    	"mem info" command
    	"police" mode
    Those will need to be fixed later (see DPDK1805 within code).

    Change-Id: Ie7d72f6ab3db68bc093c42d60d125fe86f8fbda7
    Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>
    Signed-off-by: Patrice Buriez <patrice.buriez@intel.com>