このyumの問題を解決するには： "reformdファイルがありません。"

私はFedora 20を使用しており、複数のパッケージをインストールしようとしています。例えば

sudo yum install python-matplotlib

そしてこの答えを受けましたすべて私が試したパッケージ：

Loaded plugins: langpacks, refresh-packagekit
adobe-linux-i386                                         |  951 B  00:00     
epel/i386/metalink                                       |  38 kB  00:00     
Could not parse metalink https://mirrors.fedoraproject.org/metalink repo=epel-7&arch=i386 error was 
No repomd file


One of the configured repositories failed (Unknown),
 and yum doesn't have enough cached data to continue. At this point the only
 safe thing yum can do is fail. There are a few ways to work "fix" this:

     1. Contact the upstream for the repository and get them to fix the problem.

     2. Reconfigure the baseurl/etc. for the repository, to point to a working
        upstream. This is most often useful if you are using a newer
        distribution release than is supported by the repository (and the
        packages for the previous distribution release still work).

     3. Disable the repository, so yum won't use it by default. Yum will then
        just ignore the repository until you permanently enable it again or use
        --enablerepo for temporary usage:

            yum-config-manager --disable <repoid>

     4. Configure the failing repository to be skipped, if it is unavailable.
        Note that yum will try to contact the repo. when it runs most commands,
        so will have to try and fail each time (and thus. yum will be be much
        slower). If it is a very temporary problem though, this is often a nice
        compromise:

            yum-config-manager --save --setopt=<repoid>.skip_if_unavailable=true

File /var/cache/yum/i386/20/epel/metalink.xml does not exist

私はこれらの提案を自信を持って試してみるほどよく理解していません。

インターネットで解決方法を検索してみましたが…

sudo yum clean all
sudo yum update -y

...問題には何の影響もありません。

これ...

[Harry@localhost]~% cat /etc/fedora-release
Fedora release 20 (Heisenbug)
[Harry@localhost]~% sudo yum distro-sync --releasever=20

...同じ「再文ファイルなし」エラーが発生します。

誰でもこの問題を解決するのに役立ちますか？