Update git submodules

* Update docs/submodules/fuel from branch 'master'
  - reclass: Revert virt.nic to hardcoded eth{0,1}

    Salt's virtualization model for virt:nic:default does not use real
    interface names that are present on the node, but instead it defaults
    to using "ethX" notation, that name being only a convention inside
    Salt internals.

    Moreover, the 'salt.control.virt' reclass class (located in
    /srv/salt/reclass/classes/system/salt/control) already provides a
    defalt maping between "eth{0,1}" and "br{0,1}". Using anything
    different than "eth{0,1}" will lead to 2 extra (broken) mappings.

    Reverting the changes in "virt:nic" reclass fixes both the python
    exception recently introduced, as well as the broken defaults.

    Change-Id: I5c90e3d2bc181c1ad3d87af64440439e6a41fb28
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>

diff --git a/docs/submodules/fuel b/docs/submodules/fuel
index 6a5acbe..db2144a 160000 (submodule)
--- a/docs/submodules/fuel
+++ b/docs/submodules/fuel
@@ -1 +1 @@
-Subproject commit 6a5acbe71f8ffabe752e4cd791ecda9662f4fa0e
+Subproject commit db2144a7f6ed8586bbab39fdb5ea15b171388e85