allow add_us_secondary to be turned off.

problem with test expression and nil value.

widgets/contrib/kbdlayout.lua

@@ -22,10 +22,12 @@ local function worker (args)
 
    local layouts          = args.layouts
    local settings         = args.settings or function () end
-   local add_us_secondary = args.add_us_secondary or true
+   local add_us_secondary = true
    local timeout          = args.timeout or 5
 
    local idx              = 1
+   
+   if args.add_us_secondary == false then add_us_secondary = false end
 
    -- Mouse bindings
    kbdlayout.widget:buttons(awful.util.table.join(