Fix zend_string warning

Author: sodabrew

Diff for: php_memcached.c

@@ -493,7 +493,7 @@ char *php_memc_printable_func (zend_fcall_info *fci, zend_fcall_info_cache *fci_
 	char *buffer = NULL;
 
 	if (fci->object) {
-		spprintf (&buffer, 0, "%s::%s", ZSTR_VAL(fci->object->ce->name), fci_cache->function_handler->common.function_name);
+		spprintf (&buffer, 0, "%s::%s", ZSTR_VAL(fci->object->ce->name), ZSTR_VAL(fci_cache->function_handler->common.function_name));
 	} else {
 		if (Z_TYPE (fci->function_name) == IS_OBJECT) {
 			spprintf (&buffer, 0, "%s", ZSTR_VAL(Z_OBJCE(fci->function_name)->name));