Update git submodules

Update git submodules

* Update docs/submodules/armband from branch 'master'
  - Merge "[p/openstack.nova] Allow creation of pty on aarch64"
  - [p/openstack.nova] Allow creation of pty on aarch64

    Armband uses openstack packages from Ubuntu. Those packages
    are configured to work with other packages from UCA repos. Since
    ARMband uses newer versions of certain packages than those in UCA
    (libvirt) we can allow different config without breaking anything.

    JIRA: ARMBAND-352

    Change-Id: I8f8947c3fca3b5239edb5089d3b54d0d159b4dc8
    Signed-off-by: Charalampos Kominos <charalampos.kominos@enea.com>