[DOC] fix erroneous "useallbackups" option in the doc

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 6f51804..6e57739 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -3748,7 +3748,7 @@ backup
   balancing when all other non-backup servers are unavailable. Requests coming
   with a persistence cookie referencing the server will always be served
   though. By default, only the first operational backup server is used, unless
-  the "useallbackup" option is set in the backend. See also the "useallbackup"
+  the "allbackups" option is set in the backend. See also the "allbackups"
   option.
 
 check