Geo: Adding a file to the registry may insert a null "success" value

https://sentry.gitlap.com/gitlab/geo-testbed/issues/72490/

PG::NotNullViolation: ERROR:  null value in column "success" violates not-null constraint
DETAIL:  Failing row contains (147224, lfs, 1898248, null, null, 2017-10-13 03:47:51.318828, null).

  config/initializers/active_record_locking.rb:12:in `_create_record'
    super
  app/services/geo/file_download_service.rb:48:in `update_registry'
    transfer.save
  lib/gitlab/metrics/instrumentation.rb:156:in `block in update_registry'
    trans.method_call_for(#{label.to_sym.inspect}).measure { super }
  lib/gitlab/metrics/method_call.rb:23:in `measure'
    retval = yield
  lib/gitlab/metrics/instrumentation.rb:156:in `update_registry'
    trans.method_call_for(#{label.to_sym.inspect}).measure { super }
...
(87 additional frame(s) were not displayed)

ActiveRecord::StatementInvalid: PG::NotNullViolation: ERROR:  null value in column "success" violates not-null constraint
DETAIL:  Failing row contains (147224, lfs, 1898248, null, null, 2017-10-13 03:47:51.318828, null).
: INSERT INTO "file_registry" ("file_type", "file_id", "success", "created_at") VALUES ('lfs', 1898248, NULL, '2017-10-13 03:47:51.318828') RETURNING "id"

PG::NotNullViolation: ERROR:  null value in column "success" violates not-null constraint
DETAIL:  Failing row contains (147224, lfs, 1898248, null, null, 2017-10-13 03:47:51.318828, null).
: INSERT INTO "file_registry" ("file_type", "file_id", "success", "created_at") VALUES ('lfs', 1898248, NULL, '2017-10-13 03:47:51.318828') RETURNING "id"