Access Product fields when calculating price.

{ "rules_test_rule" : {
    "LABEL" : "Display image file name on price calculation",
    "PLUGIN" : "reaction rule",
    "REQUIRES" : [ "rules", "commerce", "commerce_product_reference" ],
    "ON" : [ "commerce_product_calculate_sell_price" ],
    "IF" : [
      { "entity_is_of_type" : { "entity" : [ "commerce-line-item" ], "type" : "commerce_line_item" } },
      { "entity_has_field" : { "entity" : [ "commerce-line-item" ], "field" : "commerce_product" } },
      { "entity_exists" : {
          "type" : "commerce_product",
          "property" : "product_id",
          "value" : [ "commerce-line-item:commerce-product:product-id" ]
        }
      },
      { "entity_has_field" : {
          "entity" : [ "commerce-line-item:commerce-product" ],
          "field" : "field_image"
        }
      }
    ],
    "DO" : [
      { "drupal_message" : { "message" : [ "commerce-line-item:commerce-product:field-image:file:name" ] } }
    ]
  }
}