zsh seems to have a bug while redirecting the stderr of the 'read'
command:
% read foo 2>/dev/null <foo
zsh: no such file or directory: foo
Which causes errors to be displayed when certain files are missing.
Let's add a convenience function to manually check if the file is
readable before calling "read".
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>