changegroup: don't use 'repo' for non-repo 'self' 'repo' is a very confusing name to use for 'self', especially when it's not a repo. Also drop repo.ui member (a.k.a. self.ui) now that 'self' doesn't shadow outer 'repo' variable.

subrepo: introduce hgsubrepo._getctx() This code is already used in a couple of places, and will need to be used in others where wdir() support is needed. Trying to get the wdir() revision stored in self._substate[1] when creating the object in subrepo.subrepo() resulted in breaking various status and diff tests. This is a far less invasive change.

convert: apply the appropriate phases to the destination (issue4165) If the conversion doesn't change the hash, and the cset is public in the source, it should be public in the destination. (This can happen if file remapping is done that doesn't affect the initial commits.) This also propagates the secret phase from the source, regardless of the hash, because presumably the content is what is secret. Otherwise, the destination commit stays in the draft phase. Maybe any draft cset with an unchanged hash should be changed to public, because it has effectively been shared, but convert pretty strongly implies throwing away (or at least readonly archiving) the source repo. The change in the rollback output is because the name of the outer transaction is now 'convert', which seems more accurate. Unfortunately, the memctx won't indicate the hash prior to committing, so the proper phase can't be applied with the commit. The repo is already write locked in mercurial_sink.before().