Merge ~cjwatson/launchpad:fix-registry-can-delete-branch into launchpad:master

[Colin Watson]

Fix BranchDeletionView's checks on deletion requirements

The recent work to allow registry experts to delete branches involved changing the permission for deleting branches from `launchpad.Edit` to `launchpad.Moderate`. That work also changed `BranchDeletionView.display_deletion_requirements` to check for the `launchpad.Moderate` permission on deletion requirements (other objects that may need to be altered or deleted in order for the branch deletion to proceed). However, those other objects are always of other types (e.g. merge proposals or recipes), and so that part of the change was incorrect: we should still check `launchpad.Edit` here.

Fixes a test failure in `lib/lp/code/stories/branches/xx-branch-deletion.rst`.

[Jürgen Gmach (jugmac00)]

review: Approve

diff --git a/lib/lp/code/browser/branch.py b/lib/lp/code/browser/branch.py
index 0645172..0b4add6 100644
--- a/lib/lp/code/browser/branch.py
+++ b/lib/lp/code/browser/branch.py
@@ -983,7 +983,7 @@ class BranchDeletionView(LaunchpadFormView):
         for item, (operation, reason) in self.context.deletionRequirements(
             eager_load=True
         ).items():
-            allowed = check_permission("launchpad.Moderate", item)
+            allowed = check_permission("launchpad.Edit", item)
             reqs.append((item, operation, reason, allowed))
         return reqs