Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - CPERF: Fixes issue with known hosts

    Exporting the global var to disable ansible host key checking doesn't
    ignore known hosts in the file. To fix this, this patch sets the known
    hosts file to /dev/null.

    Reference: https://github.com/ansible/ansible/issues/9442

    Jobs currently failing due to known hosts:
    https://build.opnfv.org/ci/job/cperf-apex-csit-master/320/console

    Change-Id: Ic3470b368a056b3a3981f9555160a44018f97ebd
    Signed-off-by: Tim Rozet <trozet@redhat.com>