cleanup yum related files generated during installation

* disable all yum repos in /etc/yum.repos.d rather than just
fedora.repo and fedora-updates.repo
* remote yumdb information

rhbz#896532

Change-Id: I60981a3eeb1af43ef4d12005986e39a229d9f49e
Signed-off-by: Mike Burns <mburns@redhat.com>