build: drop support for go1.8

lib/oauthutil/oauthutil.go

@@ -590,3 +590,15 @@ func (s *authServer) Start() {
 	err = s.server.Serve(s.listener)
 	fs.Debugf(nil, "Closed auth server with error: %v", err)
 }
+
+func (s *authServer) Stop() {
+	fs.Debugf(nil, "Closing auth server")
+	if s.code != nil {
+		close(s.code)
+		s.code = nil
+	}
+	_ = s.listener.Close()
+
+	// close the server
+	_ = s.server.Close()
+}

lib/oauthutil/oauthutil_new.go

@@ -1,19 +0,0 @@
-// oauthutil parts go1.8+
-
-//+build go1.8
-
-package oauthutil
-
-import "github.com/ncw/rclone/fs"
-
-func (s *authServer) Stop() {
-	fs.Debugf(nil, "Closing auth server")
-	if s.code != nil {
-		close(s.code)
-		s.code = nil
-	}
-	_ = s.listener.Close()
-
-	// close the server
-	_ = s.server.Close()
-}

lib/oauthutil/oauthutil_old.go

@@ -1,16 +0,0 @@
-// oauthutil parts pre go1.8+
-
-//+build !go1.8
-
-package oauthutil
-
-import "github.com/ncw/rclone/fs"
-
-func (s *authServer) Stop() {
-	fs.Debugf(nil, "Closing auth server")
-	if s.code != nil {
-		close(s.code)
-		s.code = nil
-	}
-	_ = s.listener.Close()
-}