Update git submodules

* Update docs/submodules/nfvbench from branch 'master'
  - Update doc

    Change-Id: I71bcf634033c78866d6808a4604b33629710ec23
    Signed-off-by: ahothan <ahothan@cisco.com>

diff --git a/docs/submodules/nfvbench b/docs/submodules/nfvbench
index eff9ff9..e480231 160000 (submodule)
--- a/docs/submodules/nfvbench
+++ b/docs/submodules/nfvbench
@@ -1 +1 @@
-Subproject commit eff9ff971acf5c7208ab2b824b897d3183c36f3c
+Subproject commit e48023137b7010e9e1640649ea2859009a362939