decided addcomputed will not support annex.smallfiles

decided addcomputed will not support annex.smallfiles

If it did, recompute would need to somehow support recomputing
non-annexed files.

And, annex.smallfiles is typically used for configuration files or
source code kind of things, where the user doesn't want it to be an
annexed file. Computed artifacts are not likely that kind of thing.

Also, git-annex importfeed is an example of something that does support
annex.addunlocked, but does not support annex.smallfiles.