Add compatibility for Bash 3.x

The `|&` token is new in Bash 4, which is not the default on Macs (I'm not sure about Linux). Given that laptop is meant to be run on a fresh machine, `2>&1 |` seems preferable, since it'll work on the Bash 3.x, which is what comes installed by default. 

re: http://github.com/thoughtbot/laptop/issues/268