vfs: convert vfs options to new style

This also
- move in use options (Opt) from vfsflags to vfscommon
- change os.FileMode to vfscommon.FileMode in parameters
- rework vfscommon.FileMode and add tests

cmd/mountlib/mount.go

@@ -228,7 +228,7 @@ func NewMountCommand(commandName string, hidden bool, mount MountFn) *cobra.Comm
 				defer cmd.StartStats()()
 			}
 
-			mnt := NewMountPoint(mount, args[1], cmd.NewFsDir(args), &Opt, &vfsflags.Opt)
+			mnt := NewMountPoint(mount, args[1], cmd.NewFsDir(args), &Opt, &vfscommon.Opt)
 			mountDaemon, err := mnt.Mount()
 
 			// Wait for foreground mount, if any...

cmd/mountlib/rc.go

@@ -10,7 +10,7 @@ import (
 
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/rc"
-	"github.com/rclone/rclone/vfs/vfsflags"
+	"github.com/rclone/rclone/vfs/vfscommon"
 )
 
 var (
@@ -85,7 +85,7 @@ func mountRc(ctx context.Context, in rc.Params) (out rc.Params, err error) {
 		return nil, err
 	}
 
-	vfsOpt := vfsflags.Opt
+	vfsOpt := vfscommon.Opt
 	err = in.GetStructMissingOK("vfsOpt", &vfsOpt)
 	if err != nil {
 		return nil, err