submodule: remove redundant check for the_index.initialized

read_cache already performs the same check and returns immediately if
the cache has already been loaded.

Signed-off-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

submodule.c

@@ -603,7 +603,6 @@ int fetch_populated_submodules(const struct argv_array *options,
 	if (!work_tree)
 		goto out;
 
-	if (!the_index.initialized)
 	if (read_cache() < 0)
 		die("index file corrupt");