v1 does not build with latest gopass version

```
# go get -a -u gopkg.in/godo.v1
# gopkg.in/godo.v1
../../../gopkg.in/godo.v1/exec.go:243: multiple-value gopass.GetPasswd() in single-value context
```

Edit: 
Revision #2c70fa70727c953c51695f800f25d6b44abb368e of go pass builds correctly.
