`dials["cloudsql"] = func() string {` seems valid and `dials["cloudsql"] = dialFunc {` doesn' seem valid.

http://play.golang.org/p/YhzUL3x96O
http://play.golang.org/p/j6nTx75jPx

 Should I use following code?
````
func init() {
        if dials == nil {
                dials = make(map[string]dialFunc)
        }
        dials["cloudsql"] = dialFunc {
                return cloudsql.Dial(cfg.addr)
        }
}
````