Auto detect release version

release version can be found in /etc/issue.

Signed-off-by: Amos Kong <kongjianjun@gmail.com>
http://kambing.ui.edu/ is unavailable

Move it to the end of the list.

Signed-off-by: Amos Kong <kongjianjun@gmail.com>
Fix a typo in URL

It's 'Fedora' in ftp.nchu.edu.tw's URL, not 'fedora'.
BTW, the lastest synced release is Fedora 17.

http://ftp.nchu.edu.tw/Linux/Fedora/linux/releases/17/Everything/i386/os/

Signed-off-by: Amos Kong <kongjianjun@gmail.com>
Merge pull request #4 from kongove/url

auto detect release version of fedora