Make BATCH_JOB_EXECUTION#JOB_CONFIGURATION_LOCATION nullable by defau…

…lt for DB2

This commit adds DEFAULT to BATCH_JOB_EXECUTION#JOB_CONFIGURATION_LOCATION
for DB2. This fixes a SqlSyntaxErrorException with DB2 v9.

Credits to @omheni for the fix, see #4002.

Resolves #4001

spring-batch-core/src/main/resources/org/springframework/batch/core/schema-db2.sql

@@ -19,7 +19,7 @@ CREATE TABLE BATCH_JOB_EXECUTION  (
 	EXIT_CODE VARCHAR(2500) ,
 	EXIT_MESSAGE VARCHAR(2500) ,
 	LAST_UPDATED TIMESTAMP,
-	JOB_CONFIGURATION_LOCATION VARCHAR(2500) NULL,
+	JOB_CONFIGURATION_LOCATION VARCHAR(2500) DEFAULT NULL,
 	constraint JOB_INST_EXEC_FK foreign key (JOB_INSTANCE_ID)
 	references BATCH_JOB_INSTANCE(JOB_INSTANCE_ID)
 ) ;