Revert "Merge pull request #16622 from matthewd/default-debug"

This reverts commit 2602a49a86, reversing
changes made to 5d7c105768.

The explicit default was introduced in 21f6d72, so apps created with Rails < 4
have the commented out version, which means that this change would break those
apps.

railties/lib/rails/application/configuration.rb

@@ -118,7 +118,7 @@ module Rails
       end
 
       def log_level
-        @log_level ||= :debug
+        @log_level ||= Rails.env.production? ? :info : :debug
       end
 
       def colorize_logging

railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt

@@ -45,8 +45,8 @@ Rails.application.configure do
   # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
   # config.force_ssl = true
 
-  # Decrease the log volume.
-  # config.log_level = :info
+  # Set to :info to decrease the log volume.
+  config.log_level = :debug
 
   # Prepend all log lines with the following tags.
   # config.log_tags = [ :subdomain, :uuid ]