Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Fix qos statistics

    Packets dropped by QoS (because queues were full) were erroneously
    shown as idle cycles. There aee now shown as discarded packets.

    Change-Id: I01a619de621a3dfbfe11cabef257f9dec311e208
    Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index e430f53..1a7a553 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit e430f537cad603a131034d01068af7757142743d
+Subproject commit 1a7a553c5c03c60595fe1f13d4e3428f94b9c27d