Fix date_default_timezone_get()

Parameter useless
http://www.php.net/manual/en/function.date-default-timezone-get.php

+ `@` concern:
if date_default_timezone_get fails, shouldn't it fallback to 'UTC'? 
if it fails, then in line 1615,
`date_default_timezone_set($this->hive['TZ']);` 
will set 'TZ' to NULL instead of 'UTC'

maybe 
```php
'TZ'=>($ddtz=@date_default_timezone_get())?$ddtz:'UTC',
```