Invalid paths in go generate directive

[blez]

Problem statement

Invalid path in go generate directive in generated/restapi/configure*.go file

Steps to reproduce

1. Run swagger generate
   swagger generate server -f ./swagger.yaml -t ./generated --exclude-main
2. Go to generated/restapi/configure*.go
   There I have comment

//go:generate swagger generate server --target ../generated --name ExampleSwaggerServer --spec ../swagger.yaml --exclude-main

Which is not right, because swagger.yaml and generated directory are 2 levels up, but not one.
If you try to run go generate you will get an error couldn't find a swagger spec
So comment should be

//go:generate swagger generate server --target ../../generated --name ExampleSwaggerServer --spec ../../swagger.yaml --exclude-main

Environment

swagger version: v0.17.2
commit: 800a305
go version: 1.10.3
OS: Ubuntu

[fredbi]

That's right.
This statement is defined here in templates:

go-swagger/generator/templates/server/configureapi.gotmpl

Line 28 in be966a2

//go:generate swagger generate server --target {{ .TargetPath }} --name {{ .Name }} --spec {{ .SpecPath }}

The generate_xxx.go is actually put in {{ ServerPackage }} relative to {{ Target }}.

So the issue is the incorrect relative path computed by this function:

go-swagger/generator/shared.go

Line 559 in 1f7a333

func (g *GenOpts) TargetPath() string {