awful.titlebar: Only use client name in titlebar if set

Signed-off-by: Espen Wiborg <espenhw@grumblesmurf.org>
Signed-off-by: Julien Danjou <julien@danjou.info>

lib/awful/titlebar.lua.in

@@ -51,7 +51,11 @@ function add(c, args)
     local tb = capi.wibox(args)
 
     local title = capi.widget({ type = "textbox", align = "flex" })
+    if c.name then
         title.text = " " .. util.escape(c.name) .. " "
+    else
+        title.text = nil
+    end
 
     -- Redirect relevant events to the client the titlebar belongs to
     local bts =