build: more pre go1.8 workarounds removed

lib/rest/rest.go

@@ -253,7 +253,7 @@ func (api *Client) Call(opts *Opts) (resp *http.Response, err error) {
 	if opts.NoRedirect {
 		c = ClientWithNoRedirects(api.c)
 	} else {
-		c = ClientWithHeaderReset(api.c, headers)
+		c = api.c
 	}
 	if api.signer != nil {
 		err = api.signer(req)

lib/rest/rest_header_reset.go

@@ -1,15 +0,0 @@
-//+build go1.8
-
-package rest
-
-import (
-	"net/http"
-)
-
-// ClientWithHeaderReset makes a new http client which resets the
-// headers passed in on redirect
-//
-// This is now unnecessary with go1.8 so becomes a no-op
-func ClientWithHeaderReset(c *http.Client, headers map[string]string) *http.Client {
-	return c
-}

lib/rest/rest_header_reset_go17.go

@@ -1,33 +0,0 @@
-//+build !go1.8
-
-package rest
-
-import (
-	"net/http"
-
-	"github.com/pkg/errors"
-)
-
-// ClientWithHeaderReset makes a new http client which resets the
-// headers passed in on redirect
-//
-// This is only needed for go < go1.8
-func ClientWithHeaderReset(c *http.Client, headers map[string]string) *http.Client {
-	if len(headers) == 0 {
-		return c
-	}
-	clientCopy := *c
-	clientCopy.CheckRedirect = func(req *http.Request, via []*http.Request) error {
-		if len(via) >= 10 {
-			return errors.New("stopped after 10 redirects")
-		}
-		// Reset the headers in the new request
-		for k, v := range headers {
-			if v != "" {
-				req.Header.Set(k, v)
-			}
-		}
-		return nil
-	}
-	return &clientCopy
-}

lib/rest/url_test.go

@@ -1,5 +1,3 @@
-// +build go1.8
-
 package rest
 
 import (