Update git submodules

* Update docs/submodules/nfvbench from branch 'master'
  - Merge "Enable referencing for release notes"
  - Enable referencing for release notes

    Change-Id: I0188c1895d9ad19a0ab862ce7728477c01de6541
    Signed-off-by: Sofia Wallin <sofia.wallin@ericsson.com>

diff --git a/docs/submodules/nfvbench b/docs/submodules/nfvbench
index 5be3729..5c7b844 160000 (submodule)
--- a/docs/submodules/nfvbench
+++ b/docs/submodules/nfvbench
@@ -1 +1 @@
-Subproject commit 5be3729e65156be16a88d94e8943b79edf3f7eb0
+Subproject commit 5c7b844570cc94c3b54fe1555cea5c1f6a648ace