Implement final review comments from @rymai.

1. Instantiate `ProtectedBranchesAccessSelect` from `dispatcher`

2. Use `can?(user, ...)` instead of `user.can?(...)`

3. Add `DOWNTIME` notes to all migrations added in !5081.

4. Add an explicit `down` method for migrations removing the
   `developers_can_push` and `developers_can_merge` columns, ensuring that
   the columns created (on rollback) have the appropriate defaults.

5. Remove duplicate CHANGELOG entries.

6. Blank lines after guard clauses.

2 files changed, 2 insertions, 2 deletions

diff --git a/app/services/protected_branches/create_service.rb b/app/services/protected_branches/create_service.rb
index 50f79f491ce..6150a2a83c9 100644
--- a/app/services/protected_branches/create_service.rb
+++ b/app/services/protected_branches/create_service.rb
@@ -3,7 +3,7 @@ module ProtectedBranches
     attr_reader :protected_branch
 
     def execute
-      raise Gitlab::Access::AccessDeniedError unless current_user.can?(:admin_project, project)
+      raise Gitlab::Access::AccessDeniedError unless can?(current_user, :admin_project, project)
 
       protected_branch = project.protected_branches.new(params)
 
diff --git a/app/services/protected_branches/update_service.rb b/app/services/protected_branches/update_service.rb
index da4c96b3e5f..89d8ba60134 100644
--- a/app/services/protected_branches/update_service.rb
+++ b/app/services/protected_branches/update_service.rb
@@ -3,7 +3,7 @@ module ProtectedBranches
     attr_reader :protected_branch
 
     def execute(protected_branch)
-      raise Gitlab::Access::AccessDeniedError unless current_user.can?(:admin_project, project)
+      raise Gitlab::Access::AccessDeniedError unless can?(current_user, :admin_project, project)
 
       @protected_branch = protected_branch
       @protected_branch.update(params)