Bug#881692: command-not-found: I re-wrote command-not-found

[Shawn Landden]

> * Did you test your format on a slow HDD with caches dropped? It
>>   must not be slower than the Python one (that one is way too slow
>>   already) - I did, it seems to be faster (0.4 vs 0.68 seconds)
>>   - I believe the database-based C rewrite was even much faster,
>>   though
>>
> I tested with kyotocabinet backend and it was slower with dropped caches
on a hard drive (1 second), which is the slow case I am most concerned
with. Small  makes a difference. The code is at
https://github.com/shawnl/command-not-found/tree/kyotocabinet