Merge branch 'blackst0ne-rails5-update-application-controller-log-exception' into 'master'

[Rails5] Update `ApplicationController#log_exception` to fix `undefined method 'clean'` error

See merge request gitlab-org/gitlab-ce!18636

app/controllers/application_controller.rb

@@ -110,7 +110,8 @@ class ApplicationController < ActionController::Base
   def log_exception(exception)
     Raven.capture_exception(exception) if sentry_enabled?
 
-    application_trace = ActionDispatch::ExceptionWrapper.new(env, exception).application_trace
+    backtrace_cleaner = Gitlab.rails5? ? env["action_dispatch.backtrace_cleaner"] : env
+    application_trace = ActionDispatch::ExceptionWrapper.new(backtrace_cleaner, exception).application_trace
     application_trace.map! { |t| "  #{t}\n" }
     logger.error "\n#{exception.class.name} (#{exception.message}):\n#{application_trace.join}"
   end