Supports providing an alternate GOPATH using the .gopath file

I don't have a strong preference here, the idea was to make it easier if you want your GOPATH outside your source root, say in app-root/data. I think it would still work though, if relative to the source root you could still use `../data`. Let me check if that works.

That said, I *think* there is an issue with having the GOPATH *in the root* of your repo: your repo is actually one of the dependencies that needs to go in the GOPATH. That will cause:

1. to go get, your repo root is github.com/smarterclayton/goexample
2. but your GOPATH is inside that, say  github.com/smarterclayton/goexample/mygopath
3. 'go get -tags openshift ./...' will fetch stuff and put in your GOPATH, *including* github.com/smarterclayton/goexample
4. But your GOPATH *is* inside github.com/smarterclayton/goexample
5. Some kind of cyclic dependency error

----- Original Message -----
> > @@ -19,7 +19,9 @@ If you want to serve web requests (vs. running in the
> > background), you'll need t
> >  
> >  The repository contains a sample go file which will print "hello, world"
> >  when someone hits your web application - see
> >  [web.go](https://github.com/smarterclayton/openshift-go-cart/blob/master/template/web.go).
> >  
> > -Any log output will be generated to <code>$OPENSHIFT_GO_LOG_DIR</code>
> > +Any log output will be generated to <code>$OPENSHIFT_GO_LOG_DIR</code>.
> > +
> > +If you want to override the cartridge GOPATH and provide your own, create
> > and add a ".gopath" file in your repo with the desired GOPATH location,
> > *relative to the $OPENSHIFT_HOMEDIR directory*. Example of a .gopath file
> > content: `app-root/data/mygopath`.
> 
> Why does it have to be relative to my $OPENSHIFT_HOMEDIR?  Wouldn't I be
> setting my GOPATH relative to my source root?
> 
> ---
> Reply to this email directly or view it on GitHub:
> https://github.com/smarterclayton/openshift-go-cart/pull/14/files#r21938846