[MINOR][SQL] Only populate type metadata for required types such as CHAR/VARCHAR.

[dilipbiswal]

What changes were proposed in this pull request?

When reading column descriptions from hive catalog, we currently populate the metadata for all types to record the raw hive type string. In terms of processing , we need this additional metadata information for CHAR/VARCHAR types or complex type containing the CHAR/VARCHAR types.

Its a minor cleanup. I haven't created a JIRA for it.

How was this patch tested?

Test added in HiveMetastoreCatalogSuite

[SparkQA]

Test build #81708 has finished for PR 19215 at commit d29c6ff.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[dilipbiswal]

cc @gatorsmile @cloud-fan

[SparkQA]

Test build #81733 has finished for PR 19215 at commit be83f80.

• This patch fails Scala style tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #81737 has finished for PR 19215 at commit 7098295.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[gatorsmile]

LGTM

[gatorsmile]

Thanks! Merged to master.

[dilipbiswal]

many thanks @gatorsmile