Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Locate toplevel for git submodule

    Prior to git 1.8.4 the current working dir has to
    be at top-level to run git submodule update.

    Change-Id: I4d6c052364863f965e8140e56af17c09ee39ed59
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 82b0ce5..f3f8c09 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 82b0ce54c84b0b20c3d3c7c686218bb6aa06e5bb
+Subproject commit f3f8c094a817fa0f4a60ed25185b6ca226c630d1