修复了，合班缴费直接删除 需补交差价 后直接提交导致的金额为空的bug

mec-biz/src/main/java/com/ym/mec/biz/dal/entity/MusicGroupPaymentCalenderStudentDetail.java

@@ -24,7 +24,7 @@ public class MusicGroupPaymentCalenderStudentDetail {
 	private java.math.BigDecimal courseOriginalPrice;
 	
 	/** 现价 */
-	private java.math.BigDecimal courseCurrentPrice;
+	private java.math.BigDecimal courseCurrentPrice = BigDecimal.ZERO;
 
 	/** 可扣减的课程余额 */
 	private java.math.BigDecimal subCourseAmount;