Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Fix link speed when link is down at startup.

    When link is down at startup, the link_speed returned by DPDK
    is 0. This results in un-optimized latency estimates in gen and lat.
    With this fix, lat and gen do nothing until link_speed is
    properly initialized, and use the right link speed in the fast path.

    Change-Id: Id2d14b6966ccfac7cc78db3c5a74e704b42edae7
    Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index 3981ce6..4a65cd8 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit 3981ce6fed44db09af235100526ab8bc1666e38e
+Subproject commit 4a65cd849c252ac401e22debe2012d3cf48701fc