Fix incompatible logerrors type in pg_exttable

[Ray-Eldath]

closes: #21

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Change logs

This commit is directly cherry-picked from https://github.com/greenplum-db/gpdb/pull/14123.

logerrors type in pg_foreign_table has been changed from bool to char by design in GPDB7 to support log error persistence for external tables, and originally the logerrors of extension gp_exttable_fdw was changed accordingly. This PR changes the type back to preserve backward compatability.

Because the factual data are stored in pg_foreign_table and this PR only changes the display of the data, it should have no compatability implication.

Does this PR introduce any user-facing change?

No.

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[Ray-Eldath]

I reset the author of this PR from the original author of https://github.com/greenplum-db/gpdb/pull/14123 to just me. Don't know if this will cause problems. If so I can change it back.

[tuhaihe]

I reset the author of this PR from the original author of greenplum-db/gpdb#14123 to just me. Don't know if this will cause problems. If so I can change it back.

Hi @Ray-Eldath, thanks for you to point this out. If we just cherry-pick the commits for the upstream without any changes, we should keep the original author and copyright information.

[Ray-Eldath]

I reset the author of this PR from the original author of greenplum-db/gpdb#14123 to just me. Don't know if this will cause problems. If so I can change it back.

Hi @Ray-Eldath, thanks for you to point this out. If we just cherry-pick the commits for the upstream without any changes, we should keep the original author and copyright information.

but then there's a CLA issue.

[tuhaihe]

but then there's a CLA issue.

@Ray-Eldath: Sorry to confuse you. The CLA is optional, and not required, especially for the upstream contributors. Their code is already under Apache License v2.0, for us, we have got the grant to redistribute them, so It's ok to ignore the CLA. Let's keep the original copyright information, thanks!