Comment 31 for bug 758788

After a little hint from Laurynas and some clarification on the relationship between unused_tables, dict_cache handle counts and lock lists and comparing to upstream 5.6 implementation which is similar but different I think I have a fix that clears most of these issues in 5.1 by checking to see if a dict_table has any locks or pinned indexes before allowing it to be evicted from the cache.

I am still chasing down one issue that is rather hard to hit compared to these and if I can't get it soon I will just post this fix and continue on trying to finish off this last crash.