pgsql: Avoid changing stdin/stdout to binary mode on Windows unless that

Log Message:
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Avoid changing stdin/stdout to binary mode on Windows unless that is
really the source or destination of the archive.  I think this will
resolve recent complaints that password prompting is broken in pg_restore
on Windows.  Note that password prompting and reading from stdin is an
unworkable combination on Windows ... but that was true anyway.

Modified Files:
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    pgsql/src/bin/pg_dump:
        pg_backup_archiver.c (r1.114 -> r1.115)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.c.diff?r1=1.114&r2=1.115)