Update git submodules

* Update docs/submodules/bottlenecks from branch 'stable/fraser'
  - add support for dpdk scenario

    Dovetail test ran by bii shows that dpdk var needed to be set
    to let VM be successfully created by openstack

    Change-Id: I44ab09f313e38942ff1175ad05fc7521f49b855b
    Signed-off-by: Yang (Gabriel) Yu <Gabriel.yuyang@huawei.com>
    (cherry picked from commit b928421d61a01f819bd0f059b1c3b0463dfd5d6f)

diff --git a/docs/submodules/bottlenecks b/docs/submodules/bottlenecks
index 3206dad..20fe17a 160000 (submodule)
--- a/docs/submodules/bottlenecks
+++ b/docs/submodules/bottlenecks
@@ -1 +1 @@
-Subproject commit 3206dad00a2cdc73d8e77cd8316ee74cf2386475
+Subproject commit 20fe17a8b231a8de337fa379c58b9919f42cd452