F7 中添加源并设置自动选择最快的源

添加源：
我添加了两个
[root@localhost ~]# rpm -ivh http://rpm.livna.org/livna-release-7.rpm
Retrieving http://rpm.livna.org/livna-release-7.rpm
warning: /var/tmp/rpm-xfer.LCJ57g: Header V3 DSA signature: NOKEY, key ID a109b1ec

Preparing... ########################################### [100%]
1:livna-release ########################################### [100%]
[root@localhost ~]# rpm -ivh http://ftp.freshrpms.net/pub/fre ... 1.1-1.fc.noarch.rpm
Retrieving http://ftp.freshrpms.net/pub/fre ... 1.1-1.fc.noarch.rpm
warning: /var/tmp/rpm-xfer.8mtNEd: Header V3 DSA signature: NOKEY, key ID e42d547b
Preparing... ########################################### [100%]
1:freshrpms-release ########################################### [100%]
[root@localhost ~]#