[BUGFIX] includeCSS is not compressed and concatenated

The CSS files defined in page.includeCSSLibs don't get concatenated and
compressed if you enable config.compressCss and config.concatenateCss

Resolves: #65772
Releases: master, 6.2
Change-Id: I7bb72de5308dd255ff0b20f13b65d80e4a23d5cb
Reviewed-on: http://review.typo3.org/41663


Reviewed-by: Thomas Löffler <loeffler@spooner-web.de>
Reviewed-by: Alexander Stehlik <alexander.stehlik@gmail.com>
Tested-by: Alexander Stehlik <alexander.stehlik@gmail.com>
Reviewed-by: Susanne Moog <typo3@susannemoog.de>
Tested-by: Susanne Moog <typo3@susannemoog.de>