bulk: update message returned when trying to stage a file present on …

…disk

Motivation: as per ticket #10666 when a user tries to stage a file from disk it is an illegal transition.

Modification: update message displayed to user.

Result: user will know this is intended functionality.

Acked-by:Lea Morschel
Target: master
Require-book: no
Require-notes: no

modules/dcache-bulk/src/main/java/org/dcache/services/bulk/activity/plugin/pin/StageActivity.java

@@ -180,7 +180,7 @@ private void checkStageable(FileAttributes attributes) throws CacheException {
         checkPinnable(attributes);
 
         if (attributes.getRetentionPolicy() != RetentionPolicy.CUSTODIAL) {
-            throw new CacheException(INVALID_ARGS, "File not on tape.");
+            throw new CacheException(INVALID_ARGS, "Cannot stage DISK only files");
         }
     }