Merge pull request #707 from Shopify/drop-without-context

@context not always present on a Drop

lib/liquid/drop.rb

@@ -25,7 +25,7 @@ module Liquid
 
     # Catch all for the method
     def liquid_method_missing(method)
-      return nil unless @context.strict_variables
+      return nil unless @context && @context.strict_variables
       raise Liquid::UndefinedDropMethod, "undefined method #{method}"
     end