Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Merge "Parametrized network config: nic device names"
  - Parametrized network config: nic device names

    Change-Id: I94d40529261f7753ec47a0c6a8c67ecc0fb15951
    Signed-off-by: Guillermo Herrero <guillermo.herrero@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index fca7d22..6a5acbe 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit fca7d22742df82fc6e502b17ad45ebc11c0ba89b
+Subproject commit 6a5acbe71f8ffabe752e4cd791ecda9662f4fa0e