Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Revert "Freeze the galera formula to avoid update"

    This reverts commit f49340e1aac3f5e8bb009a9d0d35aa6fedba7384.
    Version has been set back to 5.6 in upstream.

    Change-Id: I06d6865e59cfbc5055322eb31cbb237075ebdcb1
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index fa58515..36a3c2f 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit fa58515facceeffd40883e36da277d56fc5e8d90
+Subproject commit 36a3c2f40e49c51fb180cd03817aad1891e6f45e