Update git submodules

* Update docs/submodules/container4nfv from branch 'master'
  - Tiny fix for istio scenario

    - disable user interactive when clean_bookinfo
    - run sleep before status check to save ci varify time

    Change-Id: I6072b85c3c941af30263101a3d4dca0537abf1fc
    Signed-off-by: QiLiang <liangqi1@huawei.com>

diff --git a/docs/submodules/container4nfv b/docs/submodules/container4nfv
index 63a58db..37e8c63 160000 (submodule)
--- a/docs/submodules/container4nfv
+++ b/docs/submodules/container4nfv
@@ -1 +1 @@
-Subproject commit 63a58db0eed6119ebceaeb74a5bd552a00c742c6
+Subproject commit 37e8c639239ca83e11c5f378b501adb9e673fcc3