mvcc: fix typo in test
mvcc: fix typo in test

Signed-off-by: Gyuho Lee <0fbd30d364d71722b926950b451cecd97b54fc29@amazon.com>

li-ang/etcd,ajityagaty/etcd,rnaveiras/etcd,cockroachdb/etcd,etcd-io/etcd,gyuho/etcd,gyuho/etcd,coreos/etcd,etcd-io/etcd,li-ang/etcd,mqliang/etcd,dannysauer/etcd,coreos/etcd,mkumatag/etcd,mkumatag/etcd,cockroachdb/etcd,mqliang/etcd,etcd-io/etcd,ajityagaty/etcd,rnaveiras/etcd,dannysauer/etcd,mkumatag/etcd,ajityagaty/etcd,rnaveiras/etcd,mqliang/etcd