Fixing https://issues.apache.org/jira/browse/AMQ-4917 : LevelDB store can fail when using durable subs.

We were browsing durable sub entries which had been concurrently GCed causing leveldb store failures which then caused the broker to restart.
Fixing bug where the DataByteArrayInputStream was not throwing EOFExceptions when reads were going past the end of the byte array.

This would make it harder to figure out when things went wrong.