Update git submodules

Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - salt.sh: Stick to older salt-formula-neutron

    Recent changes to salt-formula-neutron, more precisely [1], broke the
    compatibility with our current reclass model [2], which was not
    updated to reflect the formula change.

    Instead of locally patching the reclass model, install the latest
    compatible version of the Neutron formula:
    - 2016.12.1+201709251458.f0607d9-1xenial1;

    [1] https://github.com/salt-formulas/salt-formula-neutron/commit/
        79ffa26858d682f404984175dc1ab93863a149ad
    [2] https://github.com/Mirantis/reclass-system-salt-model

    Change-Id: Ia1bc9de9a1543f7888688be76ff3513e6b4f062b
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit f2b1d6cfe31a451b0608b9a2aadead2dcf4cfabb)