FIX: Ensure that Doubtfire logger does not rotate

Log rotation in production is done using logrotate, and should not
be done by the rails logger. This fix ensures that the Doubtfire
logger uses the default rotate settings that should write all
log messages to one file.

app/helpers/doubtfire_logger.rb

@@ -8,7 +8,7 @@ class DoubtfireLogger < ActiveSupport::Logger
   #                   is a number
   #
   # Rails.logger initialises these as nil, so we will do the same
-  @@logger = DoubtfireLogger.new(Doubtfire::Application.config.paths["log"].first, nil, nil)
+  @@logger = DoubtfireLogger.new(Doubtfire::Application.config.paths["log"].first)
 
   #
   # Singleton logger returned