Your package rubygem-file-tail failed to build from source in current rawhide. http://koji.fedoraproject.org/koji/taskinfo?taskID=5769392 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_20_Mass_Rebuild
http://koji.fedoraproject.org/koji/taskinfo?taskID=5788606 built for rawhide.