Update git submodules

* Update docs/submodules/bottlenecks from branch 'stable/fraser'
  - Modify ping test threshold

    Change the threshold to 5 VM pairs for basic common
    OPNFV verification requirements from Dovetail.
    Currently, offline test over apex pass:
    1. ping subtest1:
       https://gist.github.com/gabrielyuyang/764b7ee636ac5502d5e561a348ae909b
    2. ping subtest2:
       https://gist.github.com/gabrielyuyang/af17905a7e2379e870f492ea393c54c0

    Working on testig over compass, trying to deploy a compass
    first. We could also see the result from compass on CI
    after this patch be merged. Results in Dovetial CI will
    also be updated then.

    Change-Id: If2cfe9988c046d733b30a23de3cd569ed06496e6
    Signed-off-by: Yang (Gabriel) Yu <Gabriel.yuyang@huawei.com>
    (cherry picked from commit 62feef57918f110d423961a3989f77cf815058c6)

diff --git a/docs/submodules/bottlenecks b/docs/submodules/bottlenecks
index 3e33f5c..3bf1544 160000 (submodule)
--- a/docs/submodules/bottlenecks
+++ b/docs/submodules/bottlenecks
@@ -1 +1 @@
-Subproject commit 3e33f5c8b8ce0d1a03e7fc4378580882fbc4b446
+Subproject commit 3bf15446777a60510824e4b73da358934df03b98