OPEN - issue BATCH-364: StepScope responsibilities can be assumed by Step (not ApplicationContext)

http://jira.springframework.org/browse/BATCH-364

Instead of lazy open, throw exception is stream is used before open().

spring-batch-core/src/main/java/org/springframework/batch/core/repository/JobRepository.java

@@ -38,7 +38,7 @@ import org.springframework.batch.item.ExecutionAttributes;
  * these Id's are set, an execution can be persisted. If the object is in a
  * transient state (i.e. it has no id of it's own) then an ID will be created
  * for that specific execution, and then stored ('saved'). (NOTE: The
- * relationship between a Job/Step and Job/StepExecutions is 1:N) If an ID does
+ * relationship between a Job/Step and Job/StepExecutions is 1:N.) If an ID does
  * exist, then the execution will be stored ('updated').
  * 
  *