- follow-up to r84637:
  -> use the already captured content-type
  -> use t3lib_div::trimExplode() instead of explode()

git-svn-id: https://svn.typo3.org/TYPO3v4/Extensions/pagenotfoundehandling/trunk@84994 735d13b6-9817-0410-8766-e36946ffe9aa