Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Revert "container4nfv: Disable jobs until the project stops changing docker version""
  - Revert "container4nfv: Disable jobs until the project stops changing docker version"

    The project fixed their build script to stop reinstalling docker which downgrades it so the jobs can be enabled back now.

    https://gerrit.opnfv.org/gerrit/#/c/50603/

    This reverts commit c9aac428e09385a5893313a99b6af6652dafd216.

    Change-Id: I529850be56e30e4fdd66929809628b89e3a2ed8f