Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - [mcp] Bring in reclass system salt models

    Change-Id: I1a865b7524f3a5242544e60e6b36b1092721c58b
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 7b4fbdd..a6daf4e 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 7b4fbdd9be1a234c345b21ebf0eafcf7f5187f26
+Subproject commit a6daf4ece3f05600ad66fea55c5220d07a71cef1