jottacloud: fix token refresh failed: is not a regular file error
jottacloud: fix token refresh failed: is not a regular file error

Before this change the jottacloud token renewer would run and give the
error:

    Token refresh failed: is not a regular file

This is because the refresh runs on the root and it isn't a file.

This was fixed by ignoring that specific error.

See: https://forum.rclone.org/t/jottacloud-crypt-3-gb-copy-runs-for-a-week-without-completing/21173

ncw/rclone,ncw/rclone,ncw/rclone,ncw/rclone