Pin rspec-rails to 4-0-maintenance

Author: JonRowe

ci/script/clone_all_rspec_repos

@@ -9,7 +9,7 @@ if is_mri; then
   clone_repo "rspec-core"
   clone_repo "rspec-expectations"
   clone_repo "rspec-mocks"
-  clone_repo "rspec-rails"
+  clone_repo "rspec-rails" "4-0-maintenance"
 
   if rspec_support_compatible; then
     clone_repo "rspec-support"