Minor fix.

* libmailutils/diag/wd.c (mu_wd): Revamp the loop to ensure the proposed
way of connecting with gdb works in case of a non-zero timeout.

@@ -49,10 +49,9 @@ mu_wd (unsigned to)
   if (to)
     {
       _count_down = to;
-      while (_count_down)
+      while (_count_down--);
 	{
 	  sleep (1);
-	  _count_down--;
 	}
     }
   else