Don't hang on to failed-load activities buffers

[jdtsmith]

The magit bookmark discussion (#111) reminded me: I find it odd that activities stores its own "warning, we couldn't load this buffer" buffer in its recent buffer list. So if you load an activity, see a failed buffer restore, and then close that frame/tab, on the next load that you get a "meta" "we can't load the buffer that mentions how you couldn't load some other buffer", and so on.

I'd expect such activities-generated buffers to be omitted on save.

[alphapapa]

If we omitted those buffers, what would we display in their stead?

[alphapapa]

That would mean corrupting the window configuration that was saved. I don't see how that would be an improvement.

[jdtsmith]

And if it's the only window...

How about giving the "cannot restore" buffer that activities generates bookmark support, so at least you only get one version?

[alphapapa]

I don't feel like that would be worth the trouble. These buffers are meant to be dismissed anyway. At least, such an idea would be very near the bottom of my Emacs-related to-do list.

[alphapapa]

@jdtsmith Having said that, I'm not opposed to, e.g. making an option for a function to return the buffer to be shown in such cases, so users could configure it to be whatever they want (e.g. blank). But I don't have time to work on that myself right now. Patches welcome, though.

[jdtsmith]

No worries, can put it on the back burner and see if it bothers anyone else.