engine_rocks: NoSpace error during flush or compaction should be ignored

## Development Task

NoSpace error during flush or compaction is harmless, as the output files aren't installed to the db yet.

RocksDB already handles IOError::NoSpace nicely, see https://github.com/tikv/rocksdb/blob/f236fe443d06337ca2538414c62f70ba17b8e409/db/error_handler.cc#L230. We should recognize this case in TIKV's event listener, and do not panic.