Update git submodules

Update git submodules

* Update docs/submodules/apex from branch 'stable/danube'
  - Merge "Fixes bugs in ovs dpdk" into stable/danube
  - Fixes bugs in ovs dpdk

    Changes Include:
     - Fixes an issue where using non-1st nic admin network deployment would
       result in loss of network connectivity during deployment.
     - Fixes an issue where not specifying cores to pin to in performance
       options would result in an incorrect '0' value used for core mask.

    JIRA: APEX-452
    JIRA: APEX-453

    Change-Id: I413290161abd9b2fa39b659d5ff989da9554f603
    Signed-off-by: Tim Rozet <trozet@redhat.com>
    (cherry picked from commit c9bde98a9729dbc442ce8c0cdbc29c7d35167db6)