setup-environment-internal: use a cleanup trap
setup-environment-internal: use a cleanup trap

Install a trap handler to avoid polluting the shell environment, even in the
case of an early return (e.g. due to error).

Signed-off-by: Trevor Woerner <8835777cd84fba3d7873eabbbe1f2de2d3f25b00@gmail.com>

ndechesne/qcom-oe-manifest