Remove 'percentage done' if it is disabled

This should prevent the client to show the attribute if the admin disabled it
in the global configuration.

app/controllers/work_packages_controller.rb

@@ -63,6 +63,8 @@ class WorkPackagesController < ApplicationController
 
   # The order in here is actually important for the angular client.
   # The first 6 are always to be displayed.
+  # Beware that 'percentageDone' may be removed if the related setting is
+  # disabled.
   DEFAULT_WORK_PACKAGE_PROPERTIES = [:status, :assignee, :responsible,
                                      :date, :percentageDone, :priority,
                                      :category, :estimatedTime, :versionName, :spentTime]
@@ -460,7 +462,15 @@ class WorkPackagesController < ApplicationController
     parse_preview_data_helper :work_package, [:notes, :description]
   end
 
-  def hook_overview_attributes(initial_attributes = DEFAULT_WORK_PACKAGE_PROPERTIES)
+  def enabled_default_work_package_properties
+    @enabled_default_work_package_properties ||= begin
+                                                   properties = DEFAULT_WORK_PACKAGE_PROPERTIES
+                                                   properties.delete(:percentageDone) if Setting.work_package_done_ratio == 'disabled'
+                                                   properties
+                                                 end
+  end
+
+  def hook_overview_attributes(initial_attributes = enabled_default_work_package_properties)
     attributes = initial_attributes
     call_hook(:work_packages_overview_attributes,
               project: @project,