If error happens while persisting DB options, then it leaves temporary OPTIONS-XXXXX.dbtmp

I had:

```C
options.info_log_level = NUM_INFO_LOG_LEVELS;
```

Which is definitely an error. It should be `INFO_LEVEL`. But I had to spend 3 hours to figure out why each DB open creates temporary file and doesn't delete.

I see three points:
1. set `fail_if_options_file_error = true` by default. Why it is false ?
2. In case of error in config persisting, write message to logs.
3. run function that removes obsolete temporary files, even in case of error.