Update cache control conditional for Rails >= 5

Author: leequarella

spec/dummy/config/environments/test.rb

@@ -14,11 +14,11 @@
 
   # Configure static file server for tests with Cache-Control for performance.
   if Rails.version.start_with?("4")
-    config.public_file_server.enabled = true
-    config.public_file_server.headers = { 'Cache-Control' => 'public, max-age=3600' }
-  else
     config.serve_static_files   = true
     config.static_cache_control = 'public, max-age=3600'
+  else
+    config.public_file_server.enabled = true
+    config.public_file_server.headers = { 'Cache-Control' => 'public, max-age=3600' }
   end
 
   # Show full error reports and disable caching.