This fixes a bug in the
If one of the JNs goes down and comes back up, it may have a discontiguous set of logs in its storage directories. This means that a future getEditLogManifest call will return a manifest that has gaps - eg it may have txn 1-3 and 7-9 but be missing 4-6. This is OK because it's guaranteed that a quorum of JNs do have those edits elsewhere.
This situation currently causes an exception since the RemoteEditLogManifest constructor verifies that the returned log files form a contiguous set of edits. That was true for the NameNode but no longer true for this new usage.