Update git submodules

* Update docs/submodules/bottlenecks from branch 'master'
  - Merge "support hosts file copy"
  - support hosts file copy

    JIRA: BOTTLENECK-227

    Dovetail needs to regulate the hosts file of each docker to
    adapt SUTs. This patch is to make hosts file consistant in
    Bottlenecks-Yarstick docker.

    Change-Id: I93a57a5cac9c8d8c0a8b6660e84b8b351c455786
    Signed-off-by: Yang Yu <Gabriel.yuyang@huawei.com>

diff --git a/docs/submodules/bottlenecks b/docs/submodules/bottlenecks
index 9400c02..28ac6b8 160000 (submodule)
--- a/docs/submodules/bottlenecks
+++ b/docs/submodules/bottlenecks
@@ -1 +1 @@
-Subproject commit 9400c02df69737daf14644d1113ac9c1173fa70a
+Subproject commit 28ac6b8788b3acc561c35c9946f73abb735c1df1