After removing a variable from CEnvironment the environment was broken

 * if the variable was not found, adding new variables is not possible any more
 * if the variable was found, the environment ended directly before the next one

Fix regression of 7ac6cc65047ed4565ab9731d705d28c01f738b51.

Signed-off-by: Sven Strickroth <email@cs-ware.de>