[SPARK-6458][SQL] Better error messages for invalid data sources

Avoid unclear match errors and use `AnalysisException`.

Author: Michael Armbrust <michael@databricks.com>

Closes #5158 from marmbrus/dataSourceError and squashes the following commits:

af9f82a [Michael Armbrust] Yins comment
90c6ba4 [Michael Armbrust] Better error messages for invalid data sources