Thread: pgsql: Adjust error checks in pg_start_backup and pg_stop_backup to make

Log Message:
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Adjust error checks in pg_start_backup and pg_stop_backup to make it possible
to perform a backup without archive_mode being enabled.  This gives up some
user-error protection in order to improve usefulness for streaming-replication
scenarios.  Per discussion.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        backup.sgml (r2.153 -> r2.154)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/backup.sgml?r1=2.153&r2=2.154)
    pgsql/src/backend/access/transam:
        xlog.c (r1.406 -> r1.407)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c?r1=1.406&r2=1.407)