Update CI runner factories to not use invalid IDs

These IDs point to non-existing rows, causing the foreign key
constraints to fail.

spec/factories/ci/runner_projects.rb

 FactoryGirl.define do
   factory :ci_runner_project, class: Ci::RunnerProject do
-    runner_id 1
-    project_id 1
+    runner factory: :ci_runner
+    project factory: :empty_project
   end
 end