Potential issue with LogTransaction as it only checks in a single directory for files

When creating a new LogTransaction we try to create the new logfile in the same directory as the one we are writing to, but as we use directories.getDirectoryForNewSSTables() this might end up in "any" of the configured data directories. If it does, we will not be able to clean up leftovers as we check for files in the same directory as the logfile was created: https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/lifecycle/LogRecord.java#L163

cc Stefania Alborghetti