This helps tests 5400,5600,5700,5710 "fail correctly" rather than
give some false positives. Also ensure cleanup actions in exit trap
work correctly even if user has alias rm='rm -i'.
Signed-off-by: Ramsay Allan Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Junio C Hamano <junkio@cox.net>