rpp.c: Use LOG_ONCE macro

Author: magnumripper

src/rpp.c

@@ -134,10 +134,7 @@ static void rpp_process_rule(struct rpp_context *ctx)
 			if (strlen(conv) == strlen8(input))
 				strcpy(ctx->input->data, conv); /* Always shorter than original */
 			else {
-				static int warned;
-
-				if (!warned++)
-					log_event("- Rule preprocessor: Rejected rule(s) not fitting current internal codepage");
+				LOG_ONCE("- Rule preprocessor: Rejected rule(s) not fitting current internal codepage");
 				input[1] = '-';
 			}
 		}