Add liberty-8.0 version to metadata.yaml
Add liberty-8.0 version to metadata.yaml

Leave 2015.1-8.0 because we need to keep backward
compatibility with iso<450 at least for 2nd acceptande round.

Change-Id: I55d8791de033ee78c0b94bfbef5517ff4783e041
Partial-Bug:1535293

stackforge/fuel-plugin-detach-rabbitmq