[BUGFIX] Remove bodytext RTE field from fluidcontent elements before TYPO3 6.2

On TYPO3 6.1 the type of locallang file is still XML. This results in another path to that file in TCA and str_replace doesn't match any occurrences and therefore can't remove the RTE field definition in TCA.
Merge pull request #143 from benjaminrau/development

[BUGFIX] Remove bodytext RTE field from fluidcontent elements before TYPO3 6.2