Fix message according to actual meaning

configure.ac

@@ -948,7 +948,7 @@ AM_CONDITIONAL(STARPU_SIMGRID, test x$enable_simgrid = xyes)
 AC_SUBST(SIMGRID_CFLAGS)
 AC_SUBST(SIMGRID_LIBS)
 
-AC_MSG_CHECKING(whether blocking drivers should be disabled)
+AC_MSG_CHECKING(whether blocking drivers should be enabled)
 AC_ARG_ENABLE(blocking-drivers, [AS_HELP_STRING([--enable-blocking-drivers], [enable blocking drivers])],
 				enable_blocking=$enableval, enable_blocking=no)
 AC_MSG_RESULT($enable_blocking)