Removed cache backend option which explicitly set file permissions

 - Removed hashed_directory_umask option because it caused Cm_Cache_Backend_File class to explicitly set permissions using chmod, ignoring umask and setgid bit.
 - Zend_Cache_Backend_File class has deprecated and removed hashed_directory_umask option from Zend Framework v1.12+
 - Magento Framework does not explicitly set file & directory permissions as of v2.0.6+

Author: xtremeperf

lib/internal/Magento/Framework/App/Cache/Frontend/Factory.php

@@ -71,7 +71,6 @@ class Factory
      */
     protected $_backendOptions = [
         'hashed_directory_level' => 1,
-        'hashed_directory_umask' => 0777,
         'file_name_prefix' => 'mage',
     ];