Move warning about dhcp-renewal-time to config parsing rather

than runtime.
See RT ticket #17382 for more.

server/confpars.c

@@ -687,6 +687,26 @@ int parse_statement (cfile, group, type, host_decl, declaration)
 				return declaration;
 			}
 
+			/*
+			 * If the configuration attempts to define on option
+			 * that we ignore, then warn about it now.
+			 *
+			 * In DHCPv4 we do not use dhcp-renewal-time or
+			 * dhcp-rebinding-time, but we use these in DHCPv6.
+			 *
+			 * XXX: We may want to include a "blacklist" of 
+			 *      options we ignore in the future, as a table.
+			 */
+			if ((option->code == DHO_DHCP_LEASE_TIME) ||
+			    ((local_family != AF_INET6) && 
+			     ((option->code == DHO_DHCP_RENEWAL_TIME) ||
+			      (option->code == DHO_DHCP_REBINDING_TIME))))
+			{
+				log_error("WARNING: server ignoring option %s "
+				          "in configuration file.",
+                                          option->name);
+			}
+
 		      finish_option:
 			et = (struct executable_statement *)0;
 			if (!parse_option_statement