Replaced deprecated function call_user_method with call_user_func.

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/extracache/trunk@83257 735d13b6-9817-0410-8766-e36946ffe9aa
Raised extension version to 0.4.1.

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/extracache/trunk@83258 735d13b6-9817-0410-8766-e36946ffe9aa