read-cache: free cache entry in add_to_index in case of early return

This frees `ce` would be leaking in the error path.

Additionally a free is moved towards the return. This helps code
readability as we often have this pattern of freeing resources just
before return/exit and not in between the code.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

read-cache.c

@@ -681,15 +681,18 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 	alias = index_file_exists(istate, ce->name, ce_namelen(ce), ignore_case);
 	if (alias && !ce_stage(alias) && !ie_match_stat(istate, alias, st, ce_option)) {
 		/* Nothing changed, really */
-		free(ce);
 		if (!S_ISGITLINK(alias->ce_mode))
 			ce_mark_uptodate(alias);
 		alias->ce_flags |= CE_ADDED;
+
+		free(ce);
 		return 0;
 	}
 	if (!intent_only) {
-		if (index_path(ce->sha1, path, st, HASH_WRITE_OBJECT))
+		if (index_path(ce->sha1, path, st, HASH_WRITE_OBJECT)) {
+			free(ce);
 			return error("unable to index file %s", path);
+		}
 	} else
 		set_object_name_for_intent_to_add_entry(ce);