Change YUM config `mirrorlist` => `baseurl`
Change YUM config `mirrorlist` => `baseurl`

It was noticed that URLs with `mirrorlist` do not work reliably
behind proxy servers. Using `baseurl` fixed problems.

uvsmtid/common-salt-states,uvsmtid/common-salt-states,uvsmtid/common-salt-states,uvsmtid/common-salt-states