Update git submodules

Update git submodules

* Update docs/submodules/kvmfornfv from branch 'stable/danube'
  - Updating documents of D-release.

    This patch is used to update the documents of D-release.

    Change-Id: I9449536e340140f67e0f77ae4120bbc210809169
    Co-Authored by:Srinivas <srinivas.atmakuri@tcs.com>
    Co-Authored by:RajithaY<rajithax.yerrumsetty@intel.com>
    Co-Authored by:shravani paladugula <shravanix.paladugula@intel.com>
    Co-Authored by:Navya Bathula <navyax.bathula@intel.com>
    Signed-off-by: Gundarapu Kalyan Reddy <reddyx.gundarapu@intel.com>
    (cherry picked from commit 1f4ef5ee33f715c03a85a868f12e89744f889cff)