Comment 1 for bug 1619567

From /var/log/nailgun/app.log

IntegrityError: (psycopg2.IntegrityError) duplicate key value violates unique constraint "_task_name_deployment_graph_id_uc"
DETAIL: Key (deployment_graph_id, task_name)=(6, openstack-network-agents-sriov) already exists.
 [SQL: 'INSERT INTO deployment_graph_tasks (deployment_graph_id, task_name, version, condition, type, groups, tasks, roles, reexecute_on, refresh_on, required
_for, requires, cross_depended_by, cross_depends, parameters, _custom) VALUES (%(deployment_graph_id)s, %(task_name)s, %(version)s, %(condition)s, %(type)s, %
(groups)s, %(tasks)s, %(roles)s, %(reexecute_on)s, %(refresh_on)s, %(required_for)s, %(requires)s, %(cross_depended_by)s, %(cross_depends)s, %(parameters)s, %
(_custom)s) RETURNING deployment_graph_tasks.id'] [parameters: {'reexecute_on': [], 'tasks': [], '_custom': '{}', 'roles': [], 'groups': [], 'deployment_graph
_id': 6, 'refresh_on': [], 'requires': [], 'required_for': [], 'version': '1.0.0', 'task_name': 'openstack-network-agents-sriov', 'cross_depended_by': '[]', '
parameters': '{}', 'type': 'skipped', 'cross_depends': '[]', 'condition': None}]

Looks like last commit have broken something in tasks.