Re: Import Statistics in postgres_fdw before resorting to sampling.

>
> Changes in this release, aside from rebasing:
>
> - The generic analyze and fdw.h changes are in their own patch (0001) that
> ignores contrib/postgres_fdw entirely.
> - The option for remote_analyze has been moved to its own patch (0003).
> - The errors raised are now warnings, to ensure that we can always fall
> back to row sampling.
> - All local attributes with attstatarget > 0 must get matching remote
> statistics or the import is considered a failure.
> - The pg_restore_attribute_stats() call has been turned into a prepared
> statement, for clarity and some minor parsing savings.
> - The calls to pg_restore_relation_stats() are parameterized, but not
> prepared as this is rarely called more than once.
> - postgresStatisticsAreImportable will now disqualify a table if has
> extended statistics objects, because we can't compute those without a row
> sample.
>

Rebase