* Fix mistake in default_value handling:

raise KeyError if value is not found for given key and no default value provided.
If default value is provided and value not found for given key, return default_value.
 * Call markCacheHit only if value is retrieved from cache container.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@28050 20353a03-c40f-0410-a6d1-a30d3c3de9de