Update git submodules

Update git submodules

* Update docs/submodules/apex from branch 'stable/danube'
  - Merge "Fix quagga user and dirs" into stable/danube
  - Fix quagga user and dirs

    The rpm spec of quagga still misses the
    correct user and dir setup for quagga.

    This is the jira to remove this later on:
    https://jira.opnfv.org/projects/SDNVPN/issues/SDNVPN-130

    Change-Id: I71885a6b177443f58d0c093833e76656eb83b428
    Signed-off-by: Nikolas Hermanns <nikolas.hermanns@ericsson.com>
    (cherry picked from commit 7dcaaf6f8f7af379124c65f3a19f4890064fa97c)