fix md5 computation with non-standard bucket JAVA-160
fix md5 computation with non-standard bucket JAVA-160

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