zip.py: minor refactoring
zip.py: minor refactoring

cuckoobox/cuckoo,rodionovd/cuckoo-osx-analyzer,cuckoobox/cuckoo,cuckoobox/cuckoo,rodionovd/cuckoo-osx-analyzer,cuckoobox/cuckoo,rodionovd/cuckoo-osx-analyzer,cuckoobox/cuckoo