Fix typo in new Dbus code.

Simon's fault.
diff --git a/src/dbus.c b/src/dbus.c
index 15fed90..a2a94dc 100644
--- a/src/dbus.c
+++ b/src/dbus.c
@@ -426,7 +426,7 @@
     }
   else
     {
-      my_syslog(LOG_INFO, "Disabling --$s option from D-Bus", name);
+      my_syslog(LOG_INFO, "Disabling --%s option from D-Bus", name);
       reset_option_bool(flag);
     }