Comment 18 for bug 1208129

Thank you Jason (jasongaiser), with your debugging result I propose a patch for the issue, it will improve the code in two points:

1. use regex to detect the os version, so 'Ubuntu Remix 14.04' is also supported
2. check whether os ver is successfully detected in need_syslinux_legacy()

however I have a concern about it, in need_syslinux_legacy() before checking for version we should first check if it is an Ubuntu image. For example Debian Wheezy has version string 7.7.0, which will cause need_syslinux_legacy() to return True.