MAGETWO-39126: Cache Collisions for Static View Files Cache

Author: Yuri Kovsher

lib/internal/Magento/Framework/Cache/Core.php

@@ -29,8 +29,7 @@ class Core extends \Zend_Cache_Core
     protected function _id($cacheId)
     {
         if ($cacheId !== null) {
-            $cacheId = str_replace('-', '__', $cacheId);
-            $cacheId = str_replace('.', '___', $cacheId);
+            $cacheId = str_replace('.', '__', $cacheId); //reduce collision chances
             $cacheId = preg_replace('/([^a-zA-Z0-9_]{1,1})/', '_', $cacheId);
             if (isset($this->_options['cache_id_prefix'])) {
                 $cacheId = $this->_options['cache_id_prefix'] . $cacheId;