**Problem**
For *non-existent* Kinesis streams:
* the command `awslocal kinesis describe-stream` returns a ResourceNotFoundException (as expected) 
* whereas `describe-stream-summary` returns stream details (as if it existed).

**Expected behaviour**
It's expected that both commands return a ResourceNotFoundException for non-existent streams. It has been verified that this is the case with AWS CLI with real AWS.

**Reproduction**
```
✗ docker run -d -e SERVICES=s3,iam,kinesis localstack/localstack:0.10.2
513dcffc9a7e8f7b4c12b20972119c5fd797f269ae4cbfe62d8bc9f66a6116eb

✗ docker container ls | head -n2
CONTAINER ID        IMAGE                          COMMAND                  CREATED             STATUS              PORTS                     NAMES
513dcffc9a7e        localstack/localstack:0.10.2   "docker-entrypoint.sh"   44 seconds ago      Up 42 seconds       4567-4597/tcp, 8080/tcp   nostalgic_mcclintock

✗ docker exec -it nostalgic_mcclintock sh
/opt/code/localstack # awslocal kinesis describe-stream --stream-name idontexist
An error occurred (ResourceNotFoundException) when calling the DescribeStream operation: Stream idontexist under account 000000000000 not found.

/opt/code/localstack # awslocal kinesis describe-stream-summary --stream-name idontexist
{
    "StreamDescriptionSummary": {
        "StreamName": "idontexist",
        "StreamARN": "idontexist",
        (...)
        "OpenShardCount": 0,
        "ConsumerCount": 0
    }
}
/opt/code/localstack # awslocal kinesis list-streams
{
    "StreamNames": []
}
/opt/code/localstack # 
```
data = json.loads(to_str(data))
        action = headers.get('X-Amz-Target')
        if action == '%s.DescribeStreamSummary' % ACTION_PREFIX:
            stream_arn = data.get('StreamARN') or data['StreamName']
            
            result = {
                'StreamDescriptionSummary': {
                    'ConsumerCount': 0,
                    'EnhancedMonitoring': [],
                    'KeyId': 'string',
                    'OpenShardCount': 0,
                    'RetentionPeriodHours': 1,
                    'StreamARN': stream_arn,
                    
                    'StreamName': data['StreamName'],
                    'StreamStatus': 'ACTIVE'
                }
            }
            return result
        if action == '%s.DescribeStreamConsumer' % ACTION_PREFIX:
            consumer_arn = data.get('ConsumerARN') or data['ConsumerName']
            consumer_name = data.get('ConsumerName') or data['ConsumerARN']
            result = {
                'ConsumerDescription': {
                    'ConsumerARN': consumer_arn,