Prompt user to subscribe when marking a bug as duplicate

[Deryck Hodge]

When a bug is marked as a duplicate of another bug, subscribers to the dupe should not be subscribed the main bug automatically. The first email sent to a subscriber notifying the person that his/her bug has been marked a duplicate should offer a link where the user can subscribe to the main bug.

[Graham Binns (gmb)]

We don't even need to offer a link. The current +filebug dupe finder
offers the user the option of subscribing from the overlay if the bug
is one that affects them; we could do the same here and take the user
to the duplicated bug once their subscription is complete.

[Launchpad QA Bot (lpqabot)]

Fixed in stable r11488 <http://bazaar.launchpad.net/~launchpad-pqm/launchpad/stable/revision/11488>.

[John A Meinel (jameinel)]

Note that this "breaks" my use case of wanting to just get a simple link to the newly targeted bug, so I can read up on it. I don't want to subscribe (I'm already subscribed by subscribing to all bugs.)

[Robert Collins (lifeless)]

@John, perhaps you could file a new bug with what you need; the bug
mgmt workflow for Launchpad is optimised for new-bugs-for-new-things.
This is possibly a regression, but I doubt we had a test demonstrating
your use case before, so its more a refinement of what we should be
doing.