Locally modifying Go package

Long story - short:
I'm playing with Google App Engine - Go version. I've tried to use one of the provided libraries and found out it doesn't work as I've expected.
A appengine/remote_api Client doesn't allow to connect to localhost and custom port, only default :80. I found a place in code responsible for handling localhost connection: https://github.com/golang/appengine/blob/a5bf4a208e232b1d3d1c972da47afe05b2c5faa5/remote_api/client.go#L46

    url := url.URL{
        Scheme: "https",
        Host: host,
        Path: "/_ah/remote_api",
    }
    if host == "localhost" {  // here's the reason
        url.Scheme = "http"
    }

then open terminal, go to directory where main go_appengine package is unpacked

cd ~/Downloads/software/go_appengine
find . -name remote_api
vim ./goroot/src/pkg/appengine/remote_api

and replace the above line with:

    if regexp.MustCompile(`^localhost(:\d{1,5})?$`).MatchString(host) {

Check it here: http://play.golang.org/p/fMogPEfgc8
There's one more thing one has to do, install modified package so it's used:

goapp install ./goroot/src/pkg/appengine/remote_api/

After this, if one run's goapp run my_super_tool.go it will use modified code. Pull request to original project.