DOC: httplog does not support 'no'

(cherry picked from commit bd556bf35c33d3088b6d43d13b93515ed70a9243)
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 8593e58..fff3dbf 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -4426,10 +4426,8 @@
 
   This option may be set either in the frontend or the backend.
 
-  If this option has been enabled in a "defaults" section, it can be disabled
-  in a specific instance by prepending the "no" keyword before it. Specifying
-  only "option httplog" will automatically clear the 'clf' mode if it was set
-  by default.
+  Specifying only "option httplog" will automatically clear the 'clf' mode
+  if it was set by default.
 
   See also :  section 8 about logging.