pgsql: Make pg_dump and pg_restore handle binary archive formats

Log Message:
-----------
Make pg_dump and pg_restore handle binary archive formats correctly
when using stdout/stdin on Windows.

Modified Files:
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pgsql/src/bin/pg_dump:
pg_backup_archiver.c (r1.103 -> r1.104)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.c.diff?r1=1.103&r2=1.104)