Update git submodules

* Update docs/submodules/bottlenecks from branch 'stable/euphrates'
  - Docs update for E 5.1

    Change-Id: I53972edc64398339463824d5f8d7193a6e15481f
    Signed-off-by: Yang Yu <Gabriel.yuyang@huawei.com>
    (cherry picked from commit ec584918ae66e92c7d8b5ff41b0df4ad391d2349)

diff --git a/docs/submodules/bottlenecks b/docs/submodules/bottlenecks
index ea99f38..66fbd5f 160000 (submodule)
--- a/docs/submodules/bottlenecks
+++ b/docs/submodules/bottlenecks
@@ -1 +1 @@
-Subproject commit ea99f38bf373fea186c5b654eac547c81cab8be6
+Subproject commit 66fbd5fcfafd5dcfde58a61aab33c1812405e097