webui: delete an unused field
webui: delete an unused field

Former-commit-id: 9d8629bbb34c640c1868988a80168006bc976554 [formerly 4e31fdde4e001fe2abda4ee0832be9bebc8b7b7b]
Former-commit-id: e7fd33a0632818c1cad5472ae3e80ea24fd9ffe6
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine