Update git submodules

* Update docs/submodules/samplevnf from branch 'master'
  - Merge "Added missing file: rapidVMs.vms"
  - Added missing file: rapidVMs.vms

    This file describes flavors, flavor meta data and boot info.
    All this info can be defined in the [Default] section and will then be
    used by to create all VMs. This data can also be specified in individual
    VM sections to overule the deault values per VM.

    Change-Id: I9d59208360eacec2790e5c467d7afcbeba301251
    Signed-off-by: Luc Provoost <luc.provoost@intel.com>

diff --git a/docs/submodules/samplevnf b/docs/submodules/samplevnf
index a343e5c..3981ce6 160000 (submodule)
--- a/docs/submodules/samplevnf
+++ b/docs/submodules/samplevnf
@@ -1 +1 @@
-Subproject commit a343e5c7cabe08cd3fd1c9987f0b49f0fc59ebe2
+Subproject commit 3981ce6fed44db09af235100526ab8bc1666e38e