init: expand comments explaining config trickery

git-init may copy "config" from the templates directory and
then re-read it. There are some comments explaining what's
going on here, but they are not grouped very well with the
matching code. Let's rearrange and expand them.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/init-db.c

@@ -191,16 +191,19 @@ static int create_default_files(const char *template_path)
 	/* Just look for `init.templatedir` */
 	git_config(git_init_db_config, NULL);
 
-	/* First copy the templates -- we might have the default
+	/*
+	 * First copy the templates -- we might have the default
 	 * config file there, in which case we would want to read
 	 * from it after installing.
 	 */
 	copy_templates(template_path);
-
 	git_config(git_default_config, NULL);
-	is_bare_repository_cfg = init_is_bare_repository;
 
-	/* reading existing config may have overwrote it */
+	/*
+	 * We must make sure command-line options continue to override any
+	 * values we might have just re-read from the config.
+	 */
+	is_bare_repository_cfg = init_is_bare_repository;
 	if (init_shared_repository != -1)
 		set_shared_repository(init_shared_repository);