Fix uninitialised Net::LDAP::LdapError

Author: Laykou

lib/net/ldap/pdu.rb

@@ -123,7 +123,7 @@ def initialize(ber_object)
     when ExtendedResponse
       parse_extended_response(ber_object[1])
     else
-      raise LdapPduError.new("unknown pdu-type: #{@app_tag}")
+      raise Error.new("unknown pdu-type: #{@app_tag}")
     end
 
     parse_controls(ber_object[2]) if ber_object[2]