Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Install missing python module of jsonschema

    Change-Id: Ib903863a7a46008c93ee795083712a50a022a41d
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 5812aed..12c984a 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 5812aed26f2c56f5e1e06260d60618d019248684
+Subproject commit 12c984af6b1cb66ee7a4c53b61b96ed55d709170