Fix 404 in redirection after removing a project

Closes https://github.com/gitlabhq/gitlabhq/issues/9844

Closes #3559

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 v 8.3.0 (unreleased)
+  - Fix 404 in redirection after removing a project (Stan Hu)
   - Fix: Assignee selector is empty when 'Unassigned' is selected (Jose Corcuera)
   - Fix 500 error when update group member permission

app/controllers/projects_controller.rb

@@ -123,7 +123,7 @@ class ProjectsController < ApplicationController
     ::Projects::DestroyService.new(@project, current_user, {}).execute
     flash[:alert] = "Project '#{@project.name}' was deleted."
-    redirect_back_or_default(default: dashboard_projects_path, options: {})
+    redirect_to dashboard_projects_path
   rescue Projects::DestroyService::DestroyError => ex
     redirect_to edit_project_path(@project), alert: ex.message
   end

spec/controllers/projects_controller_spec.rb

@@ -88,6 +88,22 @@ describe ProjectsController do
     end
   end
+  describe "#destroy" do
+    let(:admin) { create(:admin) }
+
+    it "redirects to the dashboard" do
+      controller.instance_variable_set(:@project, project)
+      sign_in(admin)
+
+      orig_id = project.id
+      delete :destroy, namespace_id: project.namespace.path, id: project.path
+
+      expect { Project.find(orig_id) }.to raise_error(ActiveRecord::RecordNotFound)
+      expect(response.status).to eq(302)
+      expect(response).to redirect_to(dashboard_projects_path)
+    end
+  end
+
   describe "POST #toggle_star" do
     it "toggles star if user is signed in" do
       sign_in(user)