evolve: continue conflicted relocation content-divergence
This patch adds logic to continue an conflicted content-divergence resolution
which was interrupted while relocating one of the divergent commits.
The tests shows the there is some mishandling of copies internally which will be
fixed in next patch.
topic: use self instead of repo in topicrepo methods
Referring to repo here was somehow preventing it from being garbage-collected
(important in hgweb, where currently every request gets a new repo).