changed error code to Integer (was string).
changed error code to Integer (was string).

kay-kim/mongo-java-driver,jsonking/mongo-java-driver,jyemin/mongo-java-driver,rozza/mongo-java-driver,kevinsawicki/mongo-java-driver,PSCGroup/mongo-java-driver,kevinsawicki/mongo-java-driver,jsonking/mongo-java-driver,jyemin/mongo-java-driver,rozza/mongo-java-driver,davydotcom/mongo-java-driver,kevinsawicki/mongo-java-driver,wanggc/mongo-java-driver,davydotcom/mongo-java-driver,wanggc/mongo-java-driver,gianpaj/mongo-java-driver