In dump-only mode, use "root" as the default username instead of

"nobody" as the latter may not be available on all systems.

plugins/sudoers/testsudoers.c

@@ -185,7 +185,7 @@ main(int argc, char *argv[])
     if (argc < 2) {
 	if (!dflag)
 	    usage();
-	user_name = "nobody";
+	user_name = "root";
 	user_cmnd = user_base = "true";
     } else {
 	user_name = *argv;