push:mysql dropping unique index

i think drizzle generates the following when it needs to drop a unique index

ALTER TABLE `stage` DROP CONSTRAINT `name`;

ALTER TABLE `stage` DROP CONSTRAINT `name`;

ALTER TABLE `stage` DROP CONSTRAINT `name`;

ALTER TABLE `stage` DROP CONSTRAINT `name`;

this doesn't work - i think it should be

alter table `stage` drop key `name`

alter table `stage` drop key `name`

alter table `stage` drop key `name`

alter table `stage` drop key `name`