config: do not open browser on headless if google fs

On google fs (drive, google photos, and google cloud storage), if
headless is selected, do not open browser.

This also supplies a new option "auth-no-open-browser" for authorize
if the user does not want it.

This should fix #3323.

cmd/authorize/authorize.go

@@ -3,11 +3,18 @@ package authorize
 import (
 	"github.com/rclone/rclone/cmd"
 	"github.com/rclone/rclone/fs/config"
+	"github.com/rclone/rclone/fs/config/flags"
 	"github.com/spf13/cobra"
 )
 
+var (
+	noAutoBrowser bool
+)
+
 func init() {
 	cmd.Root.AddCommand(commandDefinition)
+	cmdFlags := commandDefinition.Flags()
+	flags.BoolVarP(cmdFlags, &noAutoBrowser, "auth-no-open-browser", "", false, "Do not automatically open auth link in default browser")
 }
 
 var commandDefinition = &cobra.Command{
@@ -16,9 +23,12 @@ var commandDefinition = &cobra.Command{
 	Long: `
 Remote authorization. Used to authorize a remote or headless
 rclone from a machine with a browser - use as instructed by
-rclone config.`,
+rclone config.
+
+Use the --auth-no-open-browser to prevent rclone to open auth
+link in default browser automatically.`,
 	Run: func(command *cobra.Command, args []string) {
 		cmd.CheckArgs(1, 3, command, args)
-		config.Authorize(args)
+		config.Authorize(args, noAutoBrowser)
 	},
 }