Replaces backup DNS server with Google's 8.8.4.4

`4.2.2.2`, whilst publicly acessible, is not officially a public DNS server. There's no obligation or guarantee of service.

This patch replaces it with `8.8.4.4`, Google's other public DNS server.
Merge pull request #3 from davefp/patch-1

Replaces backup DNS server with Google's 8.8.4.4