set target for all associations with avoid_changes enabled, it was ne…

…eded for has_one associations too

lib/active_scaffold/attribute_params.rb

@@ -116,7 +116,7 @@ def update_record_from_params(parent_record, columns, attributes, avoid_changes
 
     def update_column_from_params(parent_record, column, attribute, avoid_changes = false)
       value = column_value_from_param_value(parent_record, column, attribute, avoid_changes)
-      if avoid_changes && column.association.try(:collection?)
+      if avoid_changes && column.association
         parent_record.association(column.name).target = value
       elsif column.association && counter_cache_hack?(column.association, attribute)
         parent_record.send "#{column.association.foreign_key}=", value.try(:id)