Print proper JSON from `ozone debug ldb scan`

$ ozone debug ldb --db=/data/metadata/om.db scan --column_family=userTable
2021-03-20 16:35:03,021 [main] INFO codec.RepeatedOmKeyInfoCodec: RepeatedOmKeyInfoCodec ignorePipeline = true
2021-03-20 16:35:03,029 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
2021-03-20 16:35:03,029 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
Added definition for table:deletedTable
...
{
  "unknownFields": {
    "fields": {}
  },
  "bitField0_": 3,
  "volumeNames_": [
    "s3v",
    "vol1"
  ],
  "objectID_": -4611686018427388160,
  "updateID_": 1,
  "memoizedIsInitialized": 1,
  "memoizedSerializedSize": -1,
  "memoizedHashCode": 0,
  "memoizedSize": -1
}

$ ozone debug ldb --db=/data/metadata/om.db scan --column_family=tenantAccessIdTable --with-keys
2021-11-30 20:28:11,358 [main] INFO codec.RepeatedOmKeyInfoCodec: RepeatedOmKeyInfoCodec ignorePipeline = true
2021-11-30 20:28:11,366 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
2021-11-30 20:28:11,366 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
2021-11-30 20:28:11,378 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
2021-11-30 20:28:11,378 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
2021-11-30 20:28:11,378 [main] INFO codec.OmKeyInfoCodec: OmKeyInfoCodec ignorePipeline = true
Added definition for table:deletedTable
...
"tenantone$testuser" -> {
  "tenantId": "tenantone",
  "userPrincipal": "testuser",
  "secretKey": "secretKey1",
  "isAdmin": false,
  "isDelegatedAdmin": false
}

{
"tenantone$testuser": {
  "tenantId": "tenantone",
  "userPrincipal": "testuser",
  "secretKey": "secretKey1",
  "isAdmin": false,
  "isDelegatedAdmin": false
}
}