Update git submodules

Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Change ODL check url to be diagstatus

    With OOO the password is no longer hardcoded to 'admin' and is
    dynamically generated a run time. This causes this curl check to fail.
    Instead, use the diagstatus URL which is new in ODL and provides a more
    accurate way (without authentication) to check if ODL is ready.

    Change-Id: I7eb034cd3f20c5f5daa52a1e9b2d8e2a52118f6e
    Signed-off-by: Tim Rozet <trozet@redhat.com>