[BUGFIX] Properly define constant in CliBootstrap

Resolves: #63649
Releases: master, 6.2
Change-Id: I17dc3b8e868c1b49511fd5e039f8e37bd9d91a55
Reviewed-on: http://review.typo3.org/35154
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>