corosync.conf.5: Fix watchdog documentation

Signed-off-by: Ferenc Wágner <wferi@debian.org>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>
(cherry picked from commit 4b21de562cf119d194857d7adbe0c9d17301b07b)

man/corosync.conf.5

@@ -691,8 +691,9 @@ directive it is possible to specify options for resources.
 Possible option is:
 .TP
 watchdog_device
-This configuration option controls which watchdog device corosync try to bind to.
-The default value is /dev/watchdog. The value "no" disables the watchdog feature.
+Watchdog device to use.
+The default value is /dev/watchdog.
+The special value "off" disables watchdog usage.
 
 .SH "FILES"
 .TP