[SPARK-19763][SQL] qualified external datasource table location stored in catalog

## What changes were proposed in this pull request?

If we create a external datasource table with a non-qualified location , we should qualified it to store in catalog.

```
CREATE TABLE t(a string)
USING parquet
LOCATION '/path/xx'

CREATE TABLE t1(a string, b string)
USING parquet
PARTITIONED BY(b)
LOCATION '/path/xx'
```

when we get the table from catalog, the location should be qualified, e.g.'file:/path/xxx'
## How was this patch tested?
unit test added

Author: windpiger <songjun@outlook.com>

Closes #17095 from windpiger/tablepathQualified.