Ensure Accumulo logs good error messages for bad files.

Recently observed a tablet server logging a message about a file it could not open during split. Neither the filename or tablet were logged, making tracking the issue down difficult.

Was thinking of writing test like the following to flush this problem out.

```
foreach fileSize : 1..256
foreach operation : MAJC, MINC, SPLIT, SCAN
* Create random file of size fileSize
* Replace a tablet file with random file
* Execute operation
* Ensure filename show up in logs (filename should be unique for each loop iteration).
```

No files or existing tests are named. Start by locating the tablet-server logging path used when files fail during split, then inspect tests covering MAJC, MINC, SPLIT, and SCAN. Done means failures identify both the unique filename and tablet in the logs, with regression coverage for the affected operations.

Written by the indexing model from the issue text.