Use git_pathdup instead of xstrdup(git_path(...))

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin-config.c b/builtin-config.c
index 91fdc49..f710162 100644
--- a/builtin-config.c
+++ b/builtin-config.c
@@ -84,7 +84,7 @@
 	local = config_exclusive_filename;
 	if (!local) {
 		const char *home = getenv("HOME");
-		local = repo_config = xstrdup(git_path("config"));
+		local = repo_config = git_pathdup("config");
 		if (git_config_global() && home)
 			global = xstrdup(mkpath("%s/.gitconfig", home));
 		if (git_config_system())