[PATCH 0/5] Return of 'quickfetch' version 3

OK, attempt #3. Much shorter series as I've taken out the (messy) object memory management change. Its now unrelated to this series and may return in the near future.

 1) Fix memory leak in traverse_commit_list

The memory leak we talked about in traverse_commit_list. Its still valid for pack-objects but is unnecessary for fetch.

 2) git-fetch: Always fetch tags if the object they reference exists

I think I figured out why I said "random behavior" earlier. Please see the commit message for an updated description.

 3) run-command: Support sending stderr to /dev/null
 4) rev-list: Introduce --quiet to avoid /dev/null redirects
 5) git-fetch: avoid local fetching from alternate (again)

Pretty much the original quickfetch series, but updated with list comments and moved to builtin-fetch where it works for all types of transports and not just the native git one.