Update Travis CI email notifications
Update Travis CI email notifications

Don't notify on success, always notify on failure

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