git-config: replace use of home_config_paths()

Since home_config_paths() combines distinct functionality already
implemented by expand_user_path() and xdg_config_home(), and hides the
home config file path ~/.gitconfig. Make the code more explicit by
replacing the use of home_config_paths() with expand_user_path() and
xdg_config_home().

Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/config.c

@@ -488,10 +488,8 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 	}
 
 	if (use_global_config) {
-		char *user_config = NULL;
-		char *xdg_config = NULL;
-
-		home_config_paths(&user_config, &xdg_config, "config");
+		char *user_config = expand_user_path("~/.gitconfig");
+		char *xdg_config = xdg_config_home("config");
 
 		if (!user_config)
 			/*

config.c

@@ -1180,10 +1180,8 @@ int git_config_system(void)
 int git_config_early(config_fn_t fn, void *data, const char *repo_config)
 {
 	int ret = 0, found = 0;
-	char *xdg_config = NULL;
-	char *user_config = NULL;
-
-	home_config_paths(&user_config, &xdg_config, "config");
+	char *xdg_config = xdg_config_home("config");
+	char *user_config = expand_user_path("~/.gitconfig");
 
 	if (git_config_system() && !access_or_die(git_etc_gitconfig(), R_OK, 0)) {
 		ret += git_config_from_file(fn, git_etc_gitconfig(),