Update git submodules

Update git submodules

* Update docs/submodules/fuel from branch 'stable/euphrates'
  - Merge "salt.sh: Pin MaaS formula to last known stable ver" into stable/euphrates
  - salt.sh: Pin MaaS formula to last known stable ver

    Recent upstream changes broke MaaS machine status parsing. Pin
    the formula to the previous version until upstream provides a
    fixed package or a repo snapshot baseline.

    Change-Id: I26ebd60f40812ae47da0ca28d19c9fdcac7920da
    Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
    (cherry picked from commit c4b87dbc189e2a2f4d586d41ef5db2166c42231d)