pg_restore ignore error patch

Dear patchers,

please find a small patch submission so that "pg_restore" ignores some sql
errors.

The implementation seems quite reasonnable to me, but pg-gods may have a
different opinion. Two fields are added to the ArchiveHandler to trigger
the behavior. A count summary of ignored sql errors is printed at the end
of the restoration.

I did not fixed the "set session auth" attempt as option "-O" can already
be used to avoid it.

It validates for me, but it seems that pg_dump/pg_restore is just *NOT*
tested at all in the validation:-(. So at least I tested it.

My tests suggest that a feature of pg_restore is that it is only expected
to work with its own server. Indeed, it generates some new syntax, such as
$$ quoting, which is not compatible with older servers. This fact does not
seem to appear in the documentation.

Have a nice day,

--
Fabien Coelho - coelho@cri.ensmp.fr