pg_rewind source-server connection

Hi all,

May be it's time to document that source-server connection in pg_rewind
must be non-replication and with superuser access.
Consider this small patch for documentation.

Previous discussion here:
http://www.postgresql.org/message-id/54AEEC26.5030707@gmx.net


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Pavel Luzanov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company