shelve: find shelvedctx from bundle even if they are already in the repo We use the new "duplicates" node tracking to find the tip of the bundle even if it already exists in the repository. Such logic is not supposed to be needed in theory. If the shelve was made using internal-phase, we already know its node. Otherwise, the bundle content should have been stripped. However, handling it makes the shelve code more robust and provide a good example of "revduplicates" usage.