FBR: clean up disk space on mirrors

[Stephen John Smoogen]

1. Remove F29beta from mirrors so mirrors can keep up
/pub/fedora/linux/releases/test/29_Beta/

2. Move F27 to archives
a. Have mirrormanager point to /pub/archives/fedora/linux/27
b. Remove /pub/fedora/linux/27

--
Stephen J Smoogen.