Fix: actually enforce the 50 attribute limit.
Fix: actually enforce the 50 attribute limit.

osmium-org/osmium,osmium-org/osmium,wffurr/osmium,wffurr/osmium,wffurr/osmium,wffurr/osmium,copyliu/osmium,osmium-org/osmium,copyliu/osmium,osmium-org/osmium,copyliu/osmium