Specify namespace when retrieving password

From logs in Kibana (filter on data.namespace_name:"localregistry-nexus-cern-apb-prov-47jkr" around 18:35 29/10/2019) provisioning was failing due to this error:

fatal: [localhost]: FAILED! => {"changed": true, "cmd": "oc rsh dc/nexus cat /nexus-data/admin.password", "delta": "0:00:00.787877", "end": "2019-10-29 17:35:38.256789", "msg": "non-zero return code", "rc": 1, "start": "2019-10-29 17:35:37.468912", "stderr": "Error from server (NotFound): deploymentconfigs.apps.openshift.io \"nexus\" not found", "stderr_lines": ["Error from server (NotFound): deploymentconfigs.apps.openshift.io \"nexus\" not found"], "stdout": "", "stdout_lines": []}

APB playbooks run in a separate namespace as the namespace where the application is provisioned.