[BUGFIX] Change wording for TYPO3 dependency errors

The wording of a TYPO3 dependency error currently suggests
installing another TYPO3 version to make an extension usable -
that does not make sense.

Change the error message so it's clear that it's the extensions'
support that is missing.

Change-Id: I7a5f7acde7bebc9c3f7acda92e2522ffb979d478
Resolves: #53572
Fixes: 6.3, 6.2
Reviewed-on: http://review.typo3.org/31833
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>