[FOLLOWUP][TASK] Cleanup bootstrap

Due to the HttpUtility resolving of absolute URLs
the redirect to the install tool did not work anymore.

Resolves: #67645
Releases: master
Change-Id: Ice49e2ad25221cfdf69d4b84b54a95633bd5df21
Reviewed-on: http://review.typo3.org/40491


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Thorsten Griebenow <tgr@starfinanz.de>
Reviewed-by: Thorsten Griebenow <tgr@starfinanz.de>
Reviewed-by: Mathias Schreiber <mathias.schreiber@wmdb.de>
Tested-by: Mathias Schreiber <mathias.schreiber@wmdb.de>