Propagate Nitrogen SR2 through Deb pipelines

Nitrogen SR2 is out. Propagate it through deb pipelines.

The default deb repo in ansible-opendaylight should be updated: https://git.opendaylight.org/gerrit/gitweb?p=integration/packaging/ansible-opendaylight.git;a=blob;f=vars/main.yml;h=6f1916f08a846974c72a62554df5ca141f23fd7d;hb=HEAD#l70

The default deb repo on the stable/nitrogen branch of puppet-opendaylight, as well as the tests that assume this default, need to be updated: https://git.opendaylight.org/gerrit/gitweb?p=integration/packaging/puppet-opendaylight.git;a=blob;f=manifests/params.pp;h=988b23e61afe8f505992279af5fc28b366a74f76;hb=refs/heads/stable/nitrogen#l16