Name the cache file with registry info

Make sure different registry use the different cache file,
The official registry use .cache.json file will not change.
fix er.message mot exist in request.js

```
return cb( response.statusCode + " "
               + require("http").STATUS_CODES[response.statusCode]
		, null, data, response )
```
in requestDone will gen a er with er.meesage not exist