Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Turn off Retpoline and KPTI protection

    Based on Canonical research (https://goo.gl/QJykMa) there is
    low-risk of attack for private clouds environments, therefore
    turn off the related kernel patches & regain performance back.

    Change-Id: I661fa127241e327b07d21a29d58d584997607123
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 9b984e9..9c20ea3 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 9b984e9be0ea5e78d111f57e2ea1c156b7b816a4
+Subproject commit 9c20ea371b59a19072b124af86dc3817753872a2