kmod-modprobe: fix leak in command line option processing.

not that it should matter for the binary, but let's be strict with
leaks so running in valgrind never complains.
diff --git a/tools/kmod-modprobe.c b/tools/kmod-modprobe.c
index 2ae8af4..6379cae 100644
--- a/tools/kmod-modprobe.c
+++ b/tools/kmod-modprobe.c
@@ -1208,11 +1208,13 @@
 			puts(PACKAGE " version " VERSION);
 			if (argv != orig_argv)
 				free(argv);
+			free(config_paths);
 			return EXIT_SUCCESS;
 		case 'h':
 			help(argv[0]);
 			if (argv != orig_argv)
 				free(argv);
+			free(config_paths);
 			return EXIT_SUCCESS;
 		case '?':
 			goto cmdline_failed;