Remove a duplicate output display name
Remove a duplicate output display name

`dmg_by_event` was repeated in the dict of display names; remove the second appearance.

Former-commit-id: 00ab37bfe18e9433971d3cad07822de09a80752d [formerly 00ab37bfe18e9433971d3cad07822de09a80752d [formerly c89b258babfc2aa3be7b7262d2bfa0669e8f567e]]
Former-commit-id: 87f55d3ef7dd2ee365149cddff7a6e63ea95d084
Former-commit-id: fe54eafb952eb968cea8286a98aa67c77ef2477e
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine