Hide configuration shenanigans in a block

I'm feeling paranoid about the scope variables like redis_config_file
get defined in. Hiding it in a block to limit the scope.

config/initializers/7_cache_settings.rb

-redis_config_file = Rails.root.join('config', 'resque.yml')
+Gitlab::Application.configure do
+  redis_config_file = Rails.root.join('config', 'resque.yml')
 
-redis_url_string = if File.exists?(redis_config_file)
-                     YAML.load_file(redis_config_file)[Rails.env]
-                   else
-                     "redis://localhost:6379"
-                   end
+  redis_url_string = if File.exists?(redis_config_file)
+                       YAML.load_file(redis_config_file)[Rails.env]
+                     else
+                       "redis://localhost:6379"
+                     end
 
-# Redis::Store does not handle Unix sockets well, so let's do it for them
-redis_config_hash = Redis::Store::Factory.extract_host_options_from_uri(redis_url_string)
-redis_uri = URI.parse(redis_url_string)
-if redis_uri.scheme == 'unix'
-  redis_config_hash[:path] = redis_uri.path
-end
+  # Redis::Store does not handle Unix sockets well, so let's do it for them
+  redis_config_hash = Redis::Store::Factory.extract_host_options_from_uri(redis_url_string)
+  redis_uri = URI.parse(redis_url_string)
+  if redis_uri.scheme == 'unix'
+    redis_config_hash[:path] = redis_uri.path
+  end
 
-redis_config_hash[:namespace] = 'cache:gitlab'
+  redis_config_hash[:namespace] = 'cache:gitlab'
 
-Gitlab::Application.config.cache_store = :redis_store, redis_config_hash
+  config.cache_store = :redis_store, redis_config_hash
+end