When bin/php/ezcache.php is run in --purge mode, if you specify certain cache items they will purge all cache, not just the specified cache. This applies to the cache items that are function based, and for which 'function' is defined but not 'purge-function'.

Steps to reproduce

• Check the contents of your cache directory
• Run: php bin/php/ezcache.php --clear-id=classid --purge
• Check the contents of your cache directory again. All files are gone (BUG), only directories remain.

Expected: Only class identifier cache should have been cleared.