hyperd cannot start after set "StorageDriver=rawblock" and remove it

[teawater]

Set "StorageDriver=rawblock" in config.
Run test.
Remove it from config.

Run hyperd, got:
I1204 08:44:41.823778 113045 config.go:39] config file: %!(EXTRA string=/etc/hyper/config)
I1204 08:44:41.824201 113045 config.go:74] [/etc/hyper/config] config items: &types.HyperConfig{ConfigFile:"/etc/hyper/config", Root:"/var/lib/hyper", Host:"", GRPCHost:"", StorageDriver:"", StorageBaseSize:"", VmFactoryPolicy:"", Driver:"qemu", Kernel:"/home/teawater/kata-containers/bk/arch/x86/boot/bzImage", Initrd:"/home/teawater/hyperhq/hyperstart/build/hyper-initrd.img", Bridge:"", BridgeIP:"", DisableIptables:false, EnableVsock:false, DefaultLog:"", DefaultLogOpt:map[string]string{}, logPrefix:"[/etc/hyper/config] "}
DEBU[0000] Using default logging driver none
DEBU[0000] devicemapper: driver version is 4.35.0
DEBU[0000] devmapper: Generated prefix: docker-8:1-4983488
DEBU[0000] devmapper: Checking for existence of the pool docker-8:1-4983488-pool
DEBU[0000] devmapper: poolDataMajMin=7:2 poolMetaMajMin=7:3

DEBU[0000] devmapper: Major:Minor for device: /dev/loop2 is:7:2
DEBU[0000] devmapper: Major:Minor for device: /dev/loop3 is:7:3
DEBU[0000] devmapper: loadDeviceFilesOnStart()
DEBU[0000] devmapper: Loading data for file /var/lib/hyper/devicemapper/metadata/base
DEBU[0000] devmapper: Skipping file /var/lib/hyper/devicemapper/metadata/deviceset-metadata
DEBU[0000] devmapper: Skipping file /var/lib/hyper/devicemapper/metadata/transaction-metadata
DEBU[0000] devmapper: loadDeviceFilesOnStart() END
DEBU[0000] devmapper: constructDeviceIDMap()
DEBU[0000] devmapper: Added deviceId=1 to DeviceIdMap
DEBU[0000] devmapper: constructDeviceIDMap() END
WARN[0000] devmapper: Usage of loopback devices is strongly discouraged for production use. Please use --storage-opt dm.thinpooldev or use man docker to refer to dm.thinpooldev section.
DEBU[0000] devmapper: activateDeviceIfNeeded()
DEBU[0000] devmapper: UUID for device: /dev/mapper/docker-8:1-4983488-base is:1b20141f-476e-421a-af7e-f5cb1a3132f1
WARN[0000] devmapper: Base device already exists and has filesystem xfs on it. User specified filesystem will be ignored.
DEBU[0000] devmapper: deactivateDevice()
DEBU[0000] devmapper: removeDevice START(docker-8:1-4983488-base)
DEBU[0000] devmapper: removeDevice END(docker-8:1-4983488-base)
DEBU[0000] devmapper: deactivateDevice END()
DEBU[0000] Cleaning up old shm/mqueue mounts: start.
E1204 08:44:42.481334 113045 hyperd.go:117] The hyperd create failed, error initializing graphdriver: "/var/lib/hyper" contains other graphdrivers: overlay,rawblock; Please cleanup or explicitly choose storage driver (-s )