Update git submodules

Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - Merge "salt modules: debian_ip: Accept uppercase ifaces" into stable/euphrates
  - salt modules: debian_ip: Accept uppercase ifaces

    Since VMs are not affected by this limitation, only apply the fixup
    to baremetal nodes.

    JIRA: FUEL-299

    Change-Id: Ib94c481627538d900295df03b8c8fdc7b61cd718
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit 8f39b4895fa66223ef6293630556457f8fb9a348)