move dio to match new layout

widgets/dio_linux.lua

@@ -18,7 +18,7 @@ local os = {
 
 -- Disk I/O: provides I/O statistics for requested storage devices
 -- vicious.widgets.dio
-local dio = {}
+local dio_linux = {}
 
 
 -- Initialize function tables
@@ -70,4 +70,4 @@ local function worker(format)
 end
 -- }}}
 
-return setmetatable(dio, { __call = function(_, ...) return worker(...) end })
+return setmetatable(dio_linux, { __call = function(_, ...) return worker(...) end })