Martin Geisler <mg@aragost.com> [Mon, 17 Oct 2011 18:01:38 +0200] rev 15287
subrepo: abort in hgsubrepo._get if the destination is obstructed
Before, we deleted foo when we determined that there were zero
changesets in the foo subrepo. Any files in foo was deleted too. We
now delete foo/.hg instead, and the normal checks in hg.clone will
then abort if there are untracked files in foo.