Update git submodules

Update git submodules

* Update docs/submodules/kvmfornfv from branch 'stable/danube'
  - This patch is used to update the documents of D-release.

    Change-Id: Iccebac991c1ea0973733963743d4d1438ac153b2
    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 7d8bfd26b45b511898825a24ecf0977a336fac13)