Inconsistency between tag database and notmuch search

[Navin Kabra]

> If you can reproduce the situation, starting from a fresh 
> database,
> let us know exactly how. Otherwise it's not really feasible to 
> debug,
> IMHO.

That's what I feared. 

I'll make one or two attempts to recreate the bug, and post here 
if I succeed. Otherwise, I'll give it up and move on.

Thanks.
navin.