External dataset creation is successful on non-existent dataverse

Creating an external dataset on an external link to AWS s3 bucket on a non-existent dataverse is successfull.

Steps to reproduce - 

1. Create an external link to AWS S3 bucket.

   curl -v -u Administrator:password -X POST "http://localhost:8095/analytics/link?dataverse=myDataverse&name=myAwsLink&type=S3&accessKey=myAccessKey&secretKey=mySecretKey&region=us-west-2&serviceEndpoint=myEndpointUri"

2. Create an external dataset on that link on a non-existent dataverse.

   CREATE EXTERNAL DATASET nonExistentDataset.myDataset

   ON myS3Bucket

   AT myDataverse.myAwsLink

   USING "json-data/reviews"

   WITH { "format": "json" };