do not use member variable in export_options template

app/views/additionals/_export_options.html.slim

@@ -2,7 +2,7 @@ div id="#{export_format}-export-options" style="display: none;"
   h3.title = l :label_export_options, export_format: export_format.upcase
 
   = form_tag url, method: :get, id: "#{export_format}-export-form" do
-    = query_as_hidden_field_tags @query
+    = query_as_hidden_field_tags query
     - if defined?(selected_columns_only) && selected_columns_only
       = hidden_field_tag 'c[]', ''
     - else
@@ -15,12 +15,12 @@ div id="#{export_format}-export-options" style="display: none;"
           = radio_button_tag 'c[]', 'all_inline'
           = l :description_all_columns
 
-    - if @query.available_block_columns.any?
+    - if query.available_block_columns.any?
       fieldset#csv-export-block-columns
         legend = toggle_checkboxes_link '#csv-export-block-columns input[type=checkbox]'
-        - @query.available_block_columns.each do |column|
+        - query.available_block_columns.each do |column|
           label
-            = check_box_tag 'c[]', column.name, @query.has_column?(column), id: nil
+            = check_box_tag 'c[]', column.name, query.has_column?(column), id: nil
             = column.caption
 
     = export_csv_encoding_select_tag