Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Merge "Rework handle_esp.c (proto, DPDK<17.08, cleanup)"
  - Rework handle_esp.c (proto, DPDK<17.08, cleanup)

    - Adjust handle functions to PROX-v035+ prototype, returning 0 when all
      packets have been handled.
    - Because cryptodev API was modified in DPDK 17.08, many changes would
      be necessary to support it. For the moment, just exclude handle_esp.c
      from PROX build when using DPDK 17.08+, which will be supported later.
    - Cleanup:
      - consistent use of PROX_PANIC to cleanly fail on errors
      - consistent use of OUT_DISCARD to drop unhandled packets
      - remove "__attribute__((unused))" when parameter is actually used
      - remove unused defines, fields and variables

    Change-Id: I10d84fa184a866b4a5f87272875612aace5dd5b1
    Signed-off-by: Patrice Buriez <patrice.buriez@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index 516aad7..f608601 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit 516aad7ecf88e968940d384a1f56dca4e42a279b
+Subproject commit f608601d06f2da7dcb52f0a0da6caebd12412ad1