Update git submodules

* Update docs/submodules/container4nfv from branch 'master'
  - remove docker installation during build

    Change-Id: I2545a17d616426d7cbb2898fa30ad248bb383461
    Signed-off-by: Guo Ruijing <ruijing.guo@intel.com>

diff --git a/docs/submodules/container4nfv b/docs/submodules/container4nfv
index 93a6999..f947f3c 160000 (submodule)
--- a/docs/submodules/container4nfv
+++ b/docs/submodules/container4nfv
@@ -1 +1 @@
-Subproject commit 93a6999a536c936a9cbf6ab1e95bb4aa16bee97d
+Subproject commit f947f3cdcc686ab9ff74796c544e5c0382961a91