override #sturcture_dump so it won't silently return while doing nothing

Author: kares

lib/arjdbc/jdbc/adapter.rb

@@ -195,6 +195,11 @@ def self.bind_substitution(visitor); visitor; end
       def bind_substitution(visitor); self.class.bind_substitution(visitor); end
       private :bind_substitution
 
+      # @override default implementation (does nothing silently)
+      def structure_dump
+        raise NotImplementedError, "structure_dump not supported"
+      end
+      
       def is_a?(klass) # :nodoc:
         # This is to fake out current_adapter? conditional logic in AR tests
         if Class === klass && klass.name =~ /#{adapter_name}Adapter$/i