Your package rubygem-riot failed to build from source in current rawhide. http://koji.fedoraproject.org/koji/taskinfo?taskID=7003768 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_21_Mass_Rebuild
Created attachment 906387 [details] build.log
Created attachment 906388 [details] root.log
Created attachment 906389 [details] state.log
Fixed by updating to riot-0.12.7.