Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - Set libvirt unix_sock_group as an option

    Updated libvirt formula now supports group
    name as an option for unix socket parameter.

    Change-Id: I683e38971fe6c939fd09e95b805d611ddc596f28
    Signed-off-by: Michael Polenchuk <mpolenchuk@mirantis.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 5ceea06..0d39b12 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 5ceea06b5395115e0e45d0631e726062eb1b0d13
+Subproject commit 0d39b12184b63e155b338fff84115fef2a3f905a