Remove diagnostic message about modular layout.

There's nothing else now.

Jamroot

@@ -159,10 +159,6 @@ if $(all-headers)
 {
     constant BOOST_MODULARLAYOUT : $(all-headers) $(numeric-headers) ;
 }
-if $(BOOST_MODULARLAYOUT)
-{
-    echo modularized layout build ;
-}
 
 project boost
     : requirements <include>.