subrepo: make it possible to update to hidden subrepo revisions When a subrepo revision was hidden it was considered missing and mercurial was unable to update to the corresponding parent revision. Instead warn the user of the problem and let it choose what to do (the default is to udpate anyway).

subrepo: remove unnecessary else clause in hgsubrepo._get This revision has no behaviour change. It simply removes an unnecessary else that follows an if / return block. The change looks big because a big chunk of code has been unindented one level.

subrepo: do not try to get hidden revisions If a subrepo revision is hidden (because it was amended, for example) it does not make sense to try to "get" it from the remote subrepository. Note that in order to avoid making the change look bigger than it is, this adds an unnecessary else clause. This will be removed on a follow up patch.