Update script to drop the collection at the start, and only do the iteration
Update script to drop the collection at the start, and only do the iteration

bjori/mongo-hhvm-driver-prototype,mongodb/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver,mongodb/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver,jmikola/mongo-hhvm-driver-prototype,mongodb/mongo-hhvm-driver,jmikola/mongo-hhvm-driver,10gen-labs/mongo-hhvm-driver-prototype,bjori/mongo-hhvm-driver-prototype,10gen-labs/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver-prototype,bjori/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver,mongodb/mongo-hhvm-driver,jmikola/mongo-hhvm-driver-prototype,jmikola/mongo-hhvm-driver,bjori/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver,jmikola/mongo-hhvm-driver,mongodb-labs/mongo-hhvm-driver-prototype,10gen-labs/mongo-hhvm-driver-prototype,10gen-labs/mongo-hhvm-driver-prototype,mongodb-labs/mongo-hhvm-driver-prototype