Fixed that we corrupt CLING_CXX_PATH
Fixed that we corrupt CLING_CXX_PATH

This will fix the issue that cling will try to invoke "OFF " to find headers.

Signed-off-by: Vassil Vassilev <0b291c0bdb4e22c8b7705ceedf8e168ff73f20e8@cern.ch>

karies/cling,marsupial/cling,marsupial/cling,root-mirror/cling,root-mirror/cling,root-mirror/cling,karies/cling,marsupial/cling,root-mirror/cling,marsupial/cling,karies/cling,root-mirror/cling,root-mirror/cling,karies/cling,marsupial/cling,marsupial/cling,karies/cling,karies/cling