Bug 1061417 - [SMS] We don't properly discard the draft in some occasion...+shepherd

...s r=azasypkin
Heh, nice catch! But would not it better if we call ```store()``` inside ```Drafts.delete()``` as we do for ```Drafts.add();```? I see we have 4 usages where we do the same pattern ```Drafts.delete().store()``` and only 1 for batch deletion where it's reasonable not to save one by one, but for that case we can have optional parameter ```Drafts.delete(draft, noAutoSave)```. 

What do you think?

That also would work for ```Drafts.clear```, but looks like it's used in tests only \0/, so I don't care :)