Retry of DB update throws NPE

[gunterze]

2017-03-13 20:02:44,190 INFO  [org.dcm4chee.arc.store.impl.StoreServiceImpl] (EE-ManagedExecutorService-default-Thread-33) ARCPAS1TRT<-ARCACT1TLN(17): Failed to update DB - retry:
: javax.ejb.EJBTransactionRolledbackException: Transaction rolled back
:
2017-03-13 20:02:44,694 INFO  [org.dcm4chee.arc.store.impl.StoreServiceImpl] (EE-ManagedExecutorService-default-Thread-33) ARCPAS1TRT<-ARCACT1TLN(17): Failed to update DB - retry:
: javax.ejb.EJBException: java.lang.NullPointerException
        at org.jboss.as.ejb3.tx.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:187)
:
Caused by: java.lang.NullPointerException
        at org.dcm4chee.arc.store.impl.StoreServiceEJB.copyLocation(StoreServiceEJB.java:1147)
        at org.dcm4chee.arc.store.impl.StoreServiceEJB.copyLocations(StoreServiceEJB.java:1137)
        at org.dcm4chee.arc.store.impl.StoreServiceEJB.updateDB(StoreServiceEJB.java:220)

Caused by 2a8baa5 for #545 since 5.9.2.