Update git submodules

Update git submodules

* Update docs/submodules/armband from branch 'master'
  - p/fuel: Set volume name in source file to sdX

    By default the openstack virtual machines use virtio_blk. That causes
    certain tests in functest to fail to attach the proper number of disks.
    The solution is to switch to scsi disks for which we must also generate
    the proper openstack source file.

    JIRA: ARMBAND-376

    Change-Id: I99a4073c24f13f1eb3798b2b07cb2c16ec3688cf
    Signed-off-by: Charalampos Kominos <Charalampos.Kominos@enea.com>