pgsql: Fix bogus logic for checking data dirs' versions within pg_upgra

Fix bogus logic for checking data dirs' versions within pg_upgrade. Commit 9be95ef15 failed to cure all of the redundancy here: we were actually calling get_major_server_version() three times for each of the old and new data directories. While that's not enormously expensive, it's still sloppy.

pgsql: Fix bogus logic for checking data dirs' versions within pg_upgra

Fix bogus logic for checking data dirs' versions within pg_upgrade. Commit 9be95ef15 failed to cure all of the redundancy here: we were actually calling get_major_server_version() three times for each of the old and new data directories. While that's not enormously expensive, it's still sloppy.