BUG #13599: Backup/Restore Documentation Bug

The following bug has been logged on the website:

Bug reference:      13599
Logged by:          Joe Kemp
Email address:      jkemp@arinc.com
PostgreSQL version: 9.4.0
Operating system:   N/A
Description:

After troubleshooting some legacy backup/restore scripts in our
infrastructure it became clear a useful bit of information is missing from
the "24.3.4. Recovering Using a Continuous Archive Backup" section.  Earlier
in this section there is a mention that the backup_label file is critical
but no mention of how it is used.  I propose the second sentence of step #8
be modified so it reads “The server will go into recovery mode and proceed
to read through the archived WAL files it needs as identified in the
backup_label file.”  This would make it clear that the backup_label file is
used during the restore process rather than being an informational file that
is available if needed.