minor cleanups in code

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/rs_securedownload/trunk@85685 735d13b6-9817-0410-8766-e36946ffe9aa
bugfixes in backend module 
- wrong language label used 
- wrong param used for export 

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/rs_securedownload/trunk@85692 735d13b6-9817-0410-8766-e36946ffe9aa