新增采购询价单的时候，用单号进行为空判断，防止产生重复单据

git-svn-id: svn+ssh://10.10.101.21/source/platform/platform-b2b@10585 f3bf4e98-0cf0-11e4-a00c-a99a8b9d557d

src/main/java/com/uas/platform/b2b/dao/PurcInquiryDao.java

@@ -9,4 +9,11 @@ import com.uas.platform.b2b.model.PurcInquiry;
 @Repository
 public interface PurcInquiryDao extends JpaRepository<PurcInquiry, Long>, JpaSpecificationExecutor<PurcInquiry> {
 
+	/**
+	 * 通过询价流水号查找询价单
+	 * 
+	 * @param code
+	 * @return
+	 */
+	PurcInquiry findByCode(String code);
 }