add config-uuid to annex:: url for --sameas remotes

And use it to set annex-config-uuid in git config. This makes
using the origin special remote work after cloning.

Without the added Logs.Remote.configSet, instantiating the remote will
look at the annex-config-uuid's config in the remote log, which will be
empty, and so it will fail to find a special remote.

The added deletion of files in the alternatejournaldir is just to make
100% sure they don't get committed to the git-annex branch. Now that
they contain things that definitely should not be committed.

doc/todo/git-remote-annex_web_special_remote_support.mdwn

@@ -20,3 +20,5 @@ works, after cloning, fetching again fails:
 
     joey@darkstar:~/tmp/newp2>git fetch origin
     git-annex: no url configured for httpalso special remote
+
+> fixed that, [[done]] --[[Joey]]