To reproduce:

Create a PR that targets the wrong bug ID, for example, a Backport record instead of the main bug. Now do the following:


1. Add the correct issue as an additional issue solved by this PR using `/issue add`
2. Wait for Skara to add the issue
3. Change the title of the PR to use that bug ID

BUG: Skara will list the BUGID: TITLE line twice in the commit message

NOTE: Normally one would just change the title to refer to the new bug (i.e., skipping steps 1-2). There is no need to use the `/issue add` command, but Skara should still ensure that it removes the additional issue when that issue becomes the primary bug ID.