Add default replication to vagrant setup

vagrant/server.properties

@@ -62,6 +62,10 @@ log.dirs=KAFKA_DATADIR
 # the brokers.
 num.partitions=2
 
+# Create new topics with a replication factor of 2 so failover can be tested
+# more easily.
+default.replication.factor=2
+
 ############################# Log Flush Policy #############################
 
 # Messages are immediately written to the filesystem but by default we only fsync() to sync