Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Update Salt version to 2017.7

    Salt 2016.x has a bug with states ordering coming from 'include'
    statement. Glance/Heat DB sync is applied before package setup
    although clearly specified 'require' in state.

    Change-Id: Ic5f7ce4a7623fb208c0a5ba366802b7e02fa8b9f
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index ff8fe89..544ff4f 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit ff8fe897ccaf4c70a5c68114d8a647d59edd75ba
+Subproject commit 544ff4f35b2b449d25272a8805bbb4c7f748f1d4