[TASK] Set TYPO3 version to 4.5.39-dev

Change-Id: I1f43bd5fc9f1197ca7f6fdfd6f68c84f7f6214ff
Reviewed-on: http://review.typo3.org/34679
Reviewed-by: TYPO3 Release Team <typo3v4@typo3.org>
Tested-by: TYPO3 Release Team <typo3v4@typo3.org>