Update git submodules

* Update docs/submodules/nfvbench from branch 'stable/euphrates'
  - NFVBENCH-45 Fix typo on imix_avg_l2_size

    Change-Id: I124ca18b717220dd7f74f14c213c3a2ca3b81c60
    Signed-off-by: Kerim Gokarslan <kgokarsl@cisco.com>
    (cherry picked from commit ac95ac97f150eef9b561b966a93b934c535164b9)

diff --git a/docs/submodules/nfvbench b/docs/submodules/nfvbench
index 02f70b5..cf170f0 160000 (submodule)
--- a/docs/submodules/nfvbench
+++ b/docs/submodules/nfvbench
@@ -1 +1 @@
-Subproject commit 02f70b50b4895a884c69e38b82149c7ee6a299ce
+Subproject commit cf170f046d63f61819ab6b5a2c75b078bf34be82