epel-release-7-6.noarch.rpm no longer available

404 encountered when downloading epel rpm to install epel on centos 7.

Browsing the repository it appears that the only available version is now 7.8.

Partial output of puppet run follows:

```
Error: Execution of '/bin/rpm -i http://download.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-6.noarch.rpm' returned 1: curl: (22) The requested URL returned error: 404 Not Found
error: skipping http://download.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-6.noarch.rpm - transfer failed
Error: /Stage[main]/Sys::Redhat::Epel/Package[epel-release-7-6]/ensure: change from absent to present failed: Execution of '/bin/rpm -i http://download.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-6.noarch.rpm' returned 1: curl: (22) The requested URL returned error: 404 Not Found
error: skipping http://download.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-6.noarch.rpm - transfer failed
```

Start by locating the Sys::Redhat::Epel package declaration that produces Package[epel-release-7-6] and inspect how the EPEL RPM URL or version is set. Reproduce the Puppet run on CentOS 7 or verify the referenced repository URL; done means the declared EPEL package downloads successfully without the 404.

Written by the indexing model from the issue text.