Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Switch distrib revision to testing

    In order to avoid bleeding edge issues with nightly version of
    salt formulas, switch to "safe" testing repo source.

    Change-Id: I9d12f337c3952711cb8843943c23315795064016
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 62ac6e3..052a162 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 62ac6e35582b21f79e098b9ccf408dbb6e81eda0
+Subproject commit 052a1626da71d232431b3a9faf576a76db61f10e