Update git submodules

* Update docs/submodules/nfvbench from branch 'master'
  - StatsManager must clean up self when there is an exception in __init__

    ALso remove unused connection.py

    Change-Id: I1bf688ade511f2054e9d67edf8938df1988e4cb2
    Signed-off-by: ahothan <ahothan@cisco.com>

diff --git a/docs/submodules/nfvbench b/docs/submodules/nfvbench
index 8363410..e2bf4ed 160000 (submodule)
--- a/docs/submodules/nfvbench
+++ b/docs/submodules/nfvbench
@@ -1 +1 @@
-Subproject commit 836341027030bcb12973cb91f7d1dbdfdb3317d7
+Subproject commit e2bf4ed6d951fe9d65b6bf8af8f8dca60ed173c9