doc:locking: remove info about old behavior of locktorture

It is not useful to know what was the default at some point in the
past: remove the information.
Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Link: https://lore.kernel.org/r/20200426211429.29133-1-federico.vaga@vaga.pv.itSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/locking/locktorture.rst

@@ -110,7 +110,7 @@ stutter
 		  same period of time.  Defaults to "stutter=5", so as
 		  to run and pause for (roughly) five-second intervals.
 		  Specifying "stutter=0" causes the test to run continuously
-		  without pausing, which is the old default behavior.
+		  without pausing.
 
 shuffle_interval
 		  The number of seconds to keep the test threads affinitied