Cannot delete an identifier assignment with a sequential algorithm if it's been run at least once

The Registry needs to delete the entry in the cm_co_sequential_identifier_assignments table before deleting the entry in the cm_co_identifier_assignments table, otherwise the following error will be thrown by the database:

2015-10-03 11:45:15 Error: [PDOException] SQLSTATE[23503]: Foreign key violation: 7 ERROR: update or delete on table "cm_co_identifier_assignments" violates foreign key constraint "cm_co_sequential_identifier_as_co_identifier_assignment_id_fkey" on table "cm_co_sequential_identifier_assignments"
DETAIL: Key (id)=(5) is still referenced from table "cm_co_sequential_identifier_assignments".
Request URL: /registry/co_identifier_assignments/delete/5/co:2
Stack Trace:
#0 /var/www/html/comanage-registry-0.9.4/lib/Cake/Model/Datasource/DboSource.php(461): PDOStatement->execute(Array)
#1 /var/www/html/comanage-registry-0.9.4/lib/Cake/Model/Datasource/DboSource.php(427): DboSource->_execute('DELETE FROM "p...', Array)
#2 /var/www/html/comanage-registry-0.9.4/lib/Cake/Model/Datasource/DboSource.php(2121): DboSource->execute('DELETE FROM "p...')
#3 /var/www/html/comanage-registry-0.9.4/lib/Cake/Model/Model.php(2709): DboSource->delete(Object(CoIdentifierAssignment), Array)
#4 /var/www/html/comanage-registry-0.9.4/app/Model/AppModel.php(438): Model->delete('5', true)
#5 /var/www/html/comanage-registry-0.9.4/app/Controller/StandardController.php(314): AppModel->delete('5')
#6 [internal function]: StandardController->delete('5')
#7 /var/www/html/comanage-registry-0.9.4/lib/Cake/Controller/Controller.php(490): ReflectionMethod->invokeArgs(Object(CoIdentifierAssignmentsController), Array)
#8 /var/www/html/comanage-registry-0.9.4/lib/Cake/Routing/Dispatcher.php(193): Controller->invokeAction(Object(CakeRequest))
#9 /var/www/html/comanage-registry-0.9.4/lib/Cake/Routing/Dispatcher.php(167): Dispatcher->_invoke(Object(CoIdentifierAssignmentsController), Object(CakeRequest))
#10 /var/www/html/comanage-registry-0.9.4/app/webroot/index.php(96): Dispatcher->dispatch(Object(CakeRequest), Object(CakeResponse))
#11