Revert "[BUGFIX] Hook to modify t3lib_div::getIndpEnv return value"

This reverts commit 33e72f56

Related: #39016
Releases: 6.0

Change-Id: I33ffcb206b2d4cac3cd7b683aec8df962c22d593
Reviewed-on: http://review.typo3.org/16127
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn