Create two distinctly named FUSE config files in the docker image. The FUSE mounts will load a named config file in order to prevent resources clashes

- Use repo files instead of printing the repository via echo command
- XRootD will be installed from the eos-depend repo
- The xrd_testing image will disable xrootd from eos-depend and install from the xrootd-testing repo

Install centos-release-scl-rh package. This provides the libasan repo, which is needed when running EOS unit tests.