Fix pg_upgrade for invalid indexes
Fix pg_upgrade for invalid indexes

All versions of pg_upgrade upgraded invalid indexes caused by CREATE
INDEX CONCURRENTLY failures and marked them as valid.  The patch adds a
check to all pg_upgrade versions and throws an error during upgrade or
--check.

Backpatch to 9.2, 9.1, 9.0.  Patch slightly adjusted.

postmind-net/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,postmind-net/postgres-xl,snaga/postgres-xl,snaga/postgres-xl,snaga/postgres-xl,kmjungersen/PostgresXL,arcivanov/postgres-xl,kmjungersen/PostgresXL,kmjungersen/PostgresXL,postmind-net/postgres-xl,kmjungersen/PostgresXL,arcivanov/postgres-xl,snaga/postgres-xl,arcivanov/postgres-xl,arcivanov/postgres-xl,snaga/postgres-xl,kmjungersen/PostgresXL