Update git submodules

Update git submodules

* Update python-openstackclient from branch 'master'
  to 08b1bb70dd2154acadaa53e22a70d0d0e4d98a0f
  - Merge "taas: Use custom command classes"
  - taas: Use custom command classes

    In change I53d9058273748ecd4d4eecec5f7291d5f38ce5ab we added custom
    Command classes for typing purposes. However, the Tap-as-a-Service code
    merged around the same time and was missed. Correct this.

    Change-Id: I3a9fe20b5b8eb54708644527538f27396f29b476
    Signed-off-by: Stephen Finucane <stephenfin@redhat.com>