AbsPath should be compatible with proxy-prefixes:

- replace Config.Prefix with .Host and .APIPath
- Request .path promoted to .pathPrefix, .baseURL holds required prefix

test/e2e/kubectl.go

@@ -203,7 +203,6 @@ var _ = Describe("Kubectl client", func() {
 				Failf("Unable to parse URL %s. Error=%s", apiServer, err)
 			}
 			apiServerUrl.Scheme = "https"
-			apiServerUrl.Path = "/api"
 			if !strings.Contains(apiServer, ":443") {
 				apiServerUrl.Host = apiServerUrl.Host + ":443"
 			}